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The aviation industry, especially the commercial aviation sector, is constantly striving to improve both the way it works and its customer satisfaction. It has begun using artificial intelligence. Though AI in the aviation industry is still in the nascent stage, some progress has been made already as certain leading carriers invest in AI. To make a long story short, AI can redefine how the aviation industry goes about its work. In 2017, American Airlines conducted an app development competition with the goal of having an app developed for making baggage screening easier for passengers. The competition, named HackWars, was themed upon artificial intelligence, drones and augmented and virtual reality. The winner, known as “Team Avatar,” developed an app that would not only allow passengers determine their baggage size before arriving at the airport, but also prepay any potential baggage-related expenses. United Airlines is using Amazon’s Alexa to have certain common customer queries answered. In September 2017, United announced a collaboration with Alexa. The feature is known as the United skill. To get started, all passengers need to do is to  add the United skill to their Alexa app and then start asking questions. Alexa answers common queries correctly, such as the status of a flight by number, check-in requests and availability of Wi-Fi on a flight. The reviews so far have been mixed, which points to the fact that there is a learning curve, and it is still a long way to go before AI can fully handle customer assistance. Tracking progress is an enormous challenge that airlines will face. The first thing they need to do is to develop analytics that will help them develop and process accurate data. However, that in itself is a challenge. What kind of analytics will help? For example, customer satisfaction is going to be one of the most important factors in success. What kind of analytics will determine that airlines have been improving on customer satisfaction parameters? AI needs huge investments, and probably the biggest risk in this is smaller, especially budget airlines are going to miss out on reaping the benefits of AI fully. Does that mean that the performance of the smaller carriers will be impacted? That might not be the case, because we might be moving toward more acquisitions and mergers. Bigger airlines will have a massive appetite for acquiring smaller airlines with an eye on the market. It is not all gloom and doom though, because smaller airlines like Southwest have already shown some initiatives toward embracing AI. It is surprising that a sector as important as aviation has woken up to AI so late. As AI in aviation picks up its pace, there could probably be a few mergers, acquisitions or even closure of small airlines which will not be able to afford the investments. Now, AI seems the best option to take aviation to the next level.
6. According to paragraph 4, how is the task of tracking progress?

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The party was ............... I had expected.

Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions:
Thanks to electricity, candles are no longer a necessity in our lives, but they are still a pleasure. The warm flame of candlelight can quickly alter the mood and atmosphere of a room, often creating a  peaceful scene that electric light just cannot match.
Candles are an important part of many cultural and religious festival and have been burnt in various forms for centuries. The ancient Romans and Egyptians made candles from a type of fiber coated with wax. However, up until the nineteenth century, most candles were made from a substance called tallow, obtained from beef fat. Tallow candles were very smoky and, understandably, had an unpleasant odor.
In the 19th century, candle makers learned to separate stearin, the solid form fat used as a type of glue, from tallow and used it to harden other fats. Candles that contained stearin would burn longer than previous ones and had a better smell. Stearin is still one of the main components of modern candle- making, and the techniques used to create candles today are much the same as they have been for many years. These days, the increase range of wax dyes, perfumes and other additives that are now available make candle making a very exciting and rewarding hobby.
Sales of candles have increased greatly over the last few years, showing that they have become part of our lives again, not through necessity, but because of the magical atmosphere they create. In our increasingly stressful lives, the calming quality of candlelight has a relaxing effect that many enjoy.
For those would like to learn to make candles, finding and buying candle-making kits is easy. Candle- making is definitely enhanced by the exciting possibilities of experimentation with various materials. Be brave and try out different effects – some of the most wonderful creations can happen by accident. With a bit of practice, you will be amazed at the very professional finish that can be achieved.
Despite their delicate beauty, candles can, of course, be highly dangerous. One should never leave lit candles unattended, even for a few moments. Always make sure candles are securely placed within candleholders.
Teach your children to respect a burning candle, and of course keep burning candles away from flammable materials. Keep your home safe by remembering that a candle is magical, but fire can be very destructive. Be careful, and enjoy the beauty of your candles!

Why was stearin used in candles?

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On April 3, 1972, a man came out of the Hilton hotel in Manhattan and started walking down the street. He stopped, (1)______ his hand with a strange object in it, put it to his ear and started to talk into it. This was the beginning of mobile phone (2)_______, more than 30 years ago. That man was Motorola’s project manager, Martin Cooper, who was (3)______ his 34th birthday that day. The strange object was the first mobile phone, which was nicknamed “the shoe” because of its unusual (4)_______. Mr. Cooper had gone to New York to introduce the new phone. The first call he made was to his rival, Joe Engel at AT&T’s research centre. Engel was responsible for the development of the radiophones for cars. “I called him and said that I was talking on a real mobile phone (5)_____ I was holding in my hand,” said Cooper. “I don’t remember what he said in reply, but I’m sure he wasn’t happy.” The quality of the call was very good, because although New York had only one base station at that time, it was being used by only one user – Martin Cooper.

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Do you know which country __________ the 2022 World cup?

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When living and working in another country, there are numerous things to consider  apart from the more obvious ones of climate, language, religion, currency, etc. Some important considerations are less obvious. For example, do you have a pet or do you enjoy a hobby such as horse riding? Your animal or hobby may be perceived in a completely different light in another culture so it’s important to consider the significance given to specific animals in different parts of the world and general perceptions towards them.  One example which is often mentioned in popular press is the case of dogs. In some cultures, like the US or UK, dogs are loved and considered a great pet to have at home and with the family. In other cultures, such as those where Islam is the majority religion, dogs may be perceived as dirty or dangerous. Muslims’ treatment of dogs is still a matter of debate amongst Islamic scholars . While these animals are widely considered by many Western cultures to be ‘man’s best friend’, the Koran describes them as unhygienic. Muslims will therefore avoid touching a dog unless he can wash his hands immediately afterwards, and they will almost never keep a dog in their home.  In Iran, for instance, a cleric once denounced ‘the moral depravity’ of dog owners and even demanded their arrest. If you are an international assignee living and working in Saudi Arabia or another Arabic country, you should remember this when inviting Arab counterparts to your house in case you have a dog as a pet. This is just one example of how Islam and other cultural beliefs can impact on aspects of everyday life that someone else may not even question. A Middle Eastern man might be very surprised when going to Japan, for instance, and seeing dogs being dressed and pampered like humans and carried around in baby prams!  Dogs are not the only animals which are perceived quite differently from one culture to another. In India, for example, cows are sacred and are treated with the utmost respect. Conversely in Argentina, beef is a symbol of national pride because of its tradition and the high quality of its cuts. An Indian working in Argentina who has not done his research or participated in a cross cultural training programme such as Doing Business in Argentina may be surprised at his first welcome dinner with his Argentinean counterparts where a main dish of beef would be served.  It is therefore crucial to be aware of the specific values assigned to objects or animals in different cultures to avoid faux-pas or cultural misunderstandings, particularly when living and working in another culture. Learning how people value animals and other symbols around the world is one of the numerous cultural examples discussed in Communicaid’s intercultural training courses. Understanding how your international colleagues may perceive certain animals can help you ensure you aren’t insensitive and it may even provide you with a good topic for conversation. 
8. It can be inferred from the passage that ___________

Fill in each numbered blank with one suitable word or phrase.

Researchers in communication show that more feelings and intentions are (1) _______ and received nonverbally than verbally. Mehrabian and Wienerfollowing have stated that only 7% (2) _______ message is sent through words, with remaining 93% sent nonverbal (3) _______.

Humans use nonverbal communication because:

1. Words have limitations: There are (4) _______ areas where nonverbal communication is more (5) _______ than verbal, especially when we explain the shape, directions, personalities which are expressed nonverbally.

2. Nonverbal signal are powerful: Nonverbal cues primarily express inner (6) _______ while verbal messages deal basically with outside world.

3. Nonverbal message are likely (7) _______ more genuine: because nonverbal behaviors cannot be controlled as easily as spoken words.

4. Nonverbal signals can express feelings inappropriate to state: Social etiquette limits (8) _______ can be said, but nonverbal cues can communicate thoughts.

5. A separate communication channel is necessary to (9) _______ send complex messages: A speaker can add enormously to the complexity of the verbal message through simple nonverbal (10) _______

(1) _______

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The United States has had approximately a thousand lights as well as light towers,  range lights, and pier head lights. Michigan has the most lights of any state with over 150 past and present lights. Most of the lights in the United States have been built and maintained by the Coast Guard. As navigation has declined and as public interest in them has increased, the Coast Guard has been handing over ownership to other parties. The first navigational lights in the New World were probably lanterns hung at harbor entrances. The first lighthouse was put up by the Massachusetts Bay Colony In 1766 on Little Brewster Island at the entrance to Boston Harbor. Paid for and maintained by light dues levied on ships, the original beacon was blown up in 1776. By then there were only a dozen or so true lighthouses in the colonies. Little over a century later, there were 700 lighthouses.  The first eight erected on the West Coast in the 1850’s featured the same basic New England design: a Cape Cod dwelling with the tower rising from the center or standing close by. In New England and elsewhere, though, lighthouses reflected a variety of architectural styles. Since most stations in the Northeast were built on rocky eminences, enormous towers were not the rule. Some were made of stone and brick, others of wood or metal. Some stood on pilings or stilts: some were fastened to rock with iron rods. Farther south, from Maryland through the Florida Keys, the coast was low and sandy. It was often necessary to build tall towers there - massive structures like the majestic Cape Hatteras, North Carolina lighthouse, which was lit in 1870. At 190 feet, it is the tallest brick lighthouse in the country. Notwithstanding differences in appearance and construction, most American lighthouses shared several features: a light, living quarters, and sometimes a bell (or, later, a foghorn). They also had something else in common: a keeper and, usually, the keeper’s family. The keeper’s essential task was trimming the lantern Nick in order to maintain a steady bright flame. The earliest keepers came from every walk of life-they were seamen. Farmers, mechanics, rough mill hands-and appointments were often handed out by local customs commissioners as political plums. After the administration of lighthouses was taken over in 1852 by the United States Lighthouse 803rd, an agency of the Treasury Department, the keeper corps gradually became highly professional.  
7. The highlighted word "erected" in the passage is closest in meaning to _______

Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions:
A massage is relaxing, and makes you feel great, but did you know that it's also good for you? That's what doctors are now saying. Massage relieves pain and anxiety, eases depression and speeds up recovery from medical problems.
Research has shown that people of all ages benefit from touch. Premature infants who are held develop faster than those left alone, and healthy babies who get a lot of physical contact cry less and sleep better. Researchers are not sure why this occurs but they have also found out that touch can slow heart rate, lower blood pressure and increase levels of seratonin, the brain chemical that is linked to well-being. It also decreases levels of the stress hormone cortisol, and this in turn increases your resistance to illness.
Massage also speeds up healing. Bone-marrow transplant patients who were given massages had better neurological function than those who weren't. Furthermore, massage reduced pain by 37% in patients with chronic muscle aches.
Giving someone a massage may be as good as getting one. A study conducted by the university of Miami found that mothers suffering from depression felt better after massaging their infants. In that same study, elderly volunteers who massaged infants reported feeling less anxious and depressed.
It even works when you do it yourself; 43% of headache sufferers reported getting relief after massaging their temples and neck and smokers who were taught self-massage while trying to quit felt less anxiety and smoked less.

Patients who get massages     .

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Previously, people often only considered second-hand smoke as a welfare issue, focusing on the smell and the irritation that tobacco smoke causes to eyes, nose and throat. But now the weight of evidence for much more serious risks to health from second-hand smoke has grown too great to ignore. Tobacco smoke contains around 4,000 chemicals, including arsenic, benzene, formaldehyde and ammonia. Around 60 of these chemicals are known or suspected to cause cancer. Many of the toxic chemicals are actually more concentrated in the smoke that’s given off by the burning tip of a cigarette (sidestream smoke). Around 85 per cent of the smoke in a room where people are smoking is the more toxic sidestream smoke. By breathing in it in the atmosphere, the non-smoker is exposed to many of the same health risks as the smoker. The best known risk to smokers, lung cancer, is also more common in people regularly exposed to second-hand smoke. The Government’s Scientific Committee on Tobacco and Health (SCOTH) reported in 1998 that exposure to second-hand smoke increases the risk of lung cancer in non-smokers by 20-30 per cent. Even though they inhale only 1% of the smoke, non-smokers exposed to second-hand smoke may suffer 25 per cent of the increased risk of heart disease associated with active smoking (one recent study suggests it might be as much as 50 per cent). Just 30 minutes of breathing second-hand smoke can reduce the coronary blood supply of a non-smoker to the same level as that of a smoker. A study in New Zealand found that exposure to second-hand smoke increases the risk of stroke by 82 per cent in non-smokers. This is a serious concern, as stroke is such a common condition. Moreover, around 3.4 million people in the UK have asthma and for most of these, tobacco smoke is a trigger for an asthma attack. For someone with asthma, just one hour of exposure to second-hand smoke can cause a 20 per cent deterioration in lung function. During pregnancy, breathing in second-hand smoke increases the risk of having a baby with a low birth weight. Small babies are at much greater risk of infections and other health problems. A recent review of international research on the immediate health impact of smokefree workplace legislation found rapid and dramatic improvements. Air quality, respiratory health and levels of heart attacks and heart disease all improved substantially within months of the legislation being introduced.
7. The article states that __________

Each sentence has a mistake. Find it bychosing A B C or D

Food addictive is any chemical that food manufacturers intentional add to their products

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Peter can just get ____________ in German.

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Scientists believe that something very serious is happening to the Earth. It is becoming warmer. Scientists predict that there will be major changes in the climate during the 21st century. Coastal waters will have higher temperatures. This will have a serious effect on agriculture. Farmers will have trouble producing good crops. In warm regions, the weather will be too dry. The amount of water could decrease by 50 per cent. This would cause a large decrease in agricultural production. World temperatures could increase from 1.5 to 5.6 degrees Celsius by the middle of the 21st century. And the increase in temperature could be even greater in the Arctic and Antarctic regions. A rise in temperature could cause the great ice sheets to melt, which, in turn would raise the level of oceans by one to two meters. Many coastal cities would be underwater. Why is all this happening? The Earth and its atmosphere are kept warm by the Sun. The atmosphere lets most of the light from the Sun pass through to warm the Earth. The Earth is warmer by the sunlight and sends heat energy back into the atmosphere. Much of this energy escapes from the Earth’s atmosphere. However, some of it remains. Gases such as carbon dioxide, ozone and water vapor absorb this energy and create more heat. Then, this heat is sent back down to Earth, and the Earth becomes warmer. Recently, however, an increase of carbon dioxide in the atmosphere is causing serious problems. Too much carbon dioxide in the atmosphere prevents heat energy from escaping. Too much heat is sent back down to the Earth, and the amount of carbon dioxide in the atmosphere continues to increase. When oil, gas, and coal burn, they create large amounts of carbon dioxide. The destruction of rain forests that absorb carbon dioxide also helps to increase the amount of carbon dioxide in our atmosphere. Some scientists believe that the amount of carbon dioxide in the air will double by the late 2000s. Scientists call this warming of the Earth and its atmosphere “the greenhouse effect”. A greenhouse, made of glass and plastic, is a special place where plants are grown. The sunlight passes through the glass or plastic and warms the air inside. The heat inside escapes very slowly, so the greenhouse remains very warm. This is exactly what is happening on the Earth. Another reason why the Earth is growing warmer is because of the amount of ozone in our atmosphere. Ozone is a form of oxygen. In the upper atmosphere, very far from the Earth, a layer of ozone helps to protect the Earth from 95 percent of the harmful light that comes from the sun. If your skin receives too much of this light, you would develop skin cancer. We need the ozone layer to protect ourselves. But the ozone layer is in trouble. Scientists have observed that the ozone layer is becoming thin, and above Antarctica there is a hole. This allows too much of the sun’s dangerous light into our atmosphere and makes the Earth warmer. Scientists say we must start making changes and planning now. We need to continue to do research, so we can predict what will happen in the future. We must burn less coal, oil, and gas. Other scientists believe that the problem is not so serious. They think that the Earth is growing warmer naturally, that we don’t need to worry about it now, and that we should just get ready for life in the warmer climate. Most scientists agree that the causes of the world’s climate are very complicated. They say that we must continue to measure the amount of carbon dioxide and ozone in the atmosphere. Scientists also encourage people to learn about the changes that are occurring in the world and how we can all help protect our atmosphere  
3. The melting of the polar ice sheets will probably lead to ____

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions:
It is many peoples dream to become a world-famous artist. Unfortunately, it can be extremely difficult to make a living solely from selling your paintings or sculptures. But don’t worry because there are other jobs in the world of art that you can pursue. One possible career option is to become an art dealer.
An art dealer works on behalf of artists to help them sell works to museums and galleries around the world. To be successful at this profession, it requires a well-rounded skill set. For starters, it helps a lot if you love art and are knowledgeable about art history. Having business skills will also be quite useful, as it will be necessary to negotiate with buyers, and help the artists you represent market their work. If becoming an art dealer sounds appealing, there are several steps which you can follow. Although you  may have a love for a wide range of styles, you should start by choosing one category to focus on. Buyers usually prefer to deal with a specialist in a particular area than someone who is a jack of all trades. When selecting your focus, choose an area that you are passionate about instead of something that seems lucrative. Art trends come and go, so there is no use trying to predict what is hot. These trends will certainly change over the course of your career.
Once you selected an area to focus on, start to contact some museums, galleries, and other companies in the art world and send them your resume. The majority of art dealers begin their careers working as interns for these kinds of companies. Although these interns may be paid little, or in some cases nothing at all, the experience of learning how art businesses work will certainly serve you down the road.
It pays to be flexible in the beginning, as the most important thing is to get your foot in the door. Museums and galleries may offer you several positions including a sales assistant or a junior art consultant. Whichever job you accept, be sure to learn it well and give it your best. In addition to your responsibilities, make sure your start to network with others in your industry. As your knowledge and contacts begin to grow, more opportunities will be open to you.

What is the passage mainly about?

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“Evidence has piled up to show that our relationships, including friendships, affect  our health at a much deeper level, tweaking not just our psychology and motivation but the function and structure of our organs and cells,” writes science journalist Lydia Denworth in the book “Friendship: The Evolution, Biology, and Extraordinary Power of Life’s Fundamental Bond” (W.W. Norton), out now. The average American claims to have about four close friends, and the great majority of us have between two and six. Only 5 percent of those studied had more than eight, while 5 percent had no close friends.  Still, 20 percent of us call ourselves lonely — and the health implications are overwhelming. We’ve known about the fallout of loneliness since a 1988 Science paper concluded that being lonely “constitute[s] a major risk factor for health” equivalent to obesity, smoking and lack of physical exercise. According to Denworth’s research, lack of social contact in the elderly costs Medicare $6.7 billion a year. There are purely positive relationships, which make up about half of our social networks, and then purely negative ones, which are rare. And then there are the uncomfortably ambivalent ones that land in-between — aka “frenemies.” These ambivalent bonds make up about half of our social networks, but the research on them is pretty stark: “Ambivalent relationships are bad for us,” writes Denworth. These relationships are reportedly causing levels of inflammation, aging, blood pressure and even greater artery calcification. This is true for even not so intimate relationships, such as colleagues and neighbors, too. Sadly, about 50 percent of married view their spouses ambivalently, according to Brigham Young University researchers. According to the book, it takes between 40 and 60 hours to create a casual friendship and over 200 hours to become a “best friend.”
1. What is main topic of the passage?

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In fact, two out of three working Americans are not (1)______ in their work,  according to a Gallup survey. People who send résumés and go to interviews think that they care only about salaries and (2)______. These are important, yes, but they are not enough. To identify a satisfying job, people should be thinking about office morale and doing work that is interesting and fun.  To demonstrate this point, my colleague Kaitlin Woolley and I asked a large group of employees what made them like their present jobs, along with what factors would (3)_____ them to like future jobs.  Unsurprisingly, we found that promotions and raises were important for people both in their current job and in applying for future jobs. What was interesting, (4)______, was that the majority cared a lot about present benefits (such as doing something interesting with people they like) in their current job, but they expected not to care very much about those things in their future jobs. When envisioning themselves in the future, they predicted that they would almost solely be driven by delayed benefits like salaries.  Why are people (5)______ aware that present benefits are important in their current job, and yet expect not to care about those benefits in the future? Why, for example, does a student who cannot sit through a boring two-hour lecture think she would be satisfied by a boring but well-paying job?

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Architect Ricardo Rosa, who is working in the center of quite busy Batheaston, England, no longer has to deal with heavy traffic on his way to work. He has given up the road - now he canoes along the river between work and home. Before setting off on the three-kilometer journey to work in the nearby town of Batheaston, Ricardo puts on a special jacket and trousers over his suit so he doesn’t get wet. When he gets there, he leaves the canoe locked up with the bicycles outside his office. He began canoeing to work after he was lent a canoe by a colleague and found instructions on how to use it on the internet. The experiment has been so successful that Ricardo now says he won’t go back to driving or cycling. He says, “At first I was a bit nervous because I had never canoed before. But I’m getting much better. It’s been very windy and rainy recently and I’ve been alright. It makes the trip more exciting. I haven’t fallen into the water yet, but I’m sure I will one day and have to sit in my wet work clothes all day. Standing up to get in and out is the most dangerous point.” Some of the people he works with are now thinking of doing the same thing themselves. They already try to help the environment in other ways. The office has its own vegetable garden outside and one employee has left his home to live on a boat. Ricardo says, “I’m hoping they’ll join me. Canoeing takes longer than going by car, but it’s a lot more pleasant. It’s a great way of getting fit and breaking the routine. It feels like you’re on holiday.”  
1. What is the writer’s main purpose in writing this text?

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I went to a restaurant last night. I was the ten thousandth customer, so my dinner was on the ___________

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Light-emitting diodes (LEDs) are now considered the future of lighting due to a lower energy requirement to run, a lower monthly price tag, and a longer life than traditional incandescent light bulbs. Nick Holonyak, an American scientist at General Electric, accidently invented the red LED light while trying to create a laser in the early 1960s. As with other inventors, the principle that some semiconductors glowed when an electric current was applied had been known since the early 1900s, but Holonyak was the first to patent it for use as a light fixture. Within a few years, yellow and green LEDs were added to the mix and used in several applications including indicator lights, calculator displays, and traffic lights, according to the DOE. The blue LED was created in the early 1990s by Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura, a group of Japanese and American scientists, and for which they won the 2014 Nobel Prize in Physics. The blue LED allowed scientists to create white LED light bulbs by coating the diodes with phosphor Today, lighting choices have expanded and people can choose different types of light bulbs, including compact fluorescent (CFL) bulbs work by heating a gas that produces ultraviolet light and LED bulbs. Several lighting companies are pushing the boundaries of what light bulbs can do, including Phillips and Stack. Phillips is one of several companies that have created wireless light bulbs that can be controlled via smartphone app. The Phillips Hue uses LED technology that can quickly be turned on or off or dimmed by a flick on a smart phone screen and can also be programmed. The higher-end Hue light bulbs can even be set to a large range of colors (only about sixteen million) and synced with music, movies, and video games. Stack, begun by engineers from Tesla and NASA, developed a smart light bulb using LED technology with a wide range of functions. It can automatically sense the ambient lighting and adjust as needed, it turns off and on via motion sensor when someone enters the room, can be used as a wake up alert, and even adjusts color throughout the day to fit with human’s natural circadian cycles and patterns of natural light. The light bulbs also have a built-in learning program that adapts to inputs given by residents over time. And all of these functions can be programmed or monitored from any smart phone or tablet. It is estimated that Stack smart light bulbs can use about sixty percent less energy than a typical LED light bulb and lasts between twenty and thirty thousand hours depending on the model . These light bulbs are compatible (or soon will be) with many of the options for turning an entire home into a smart home including usage with Amazon Alexa, Google Home, and Apple HomeKit.
5. According to paragraph 5, what can be done with the higher-end Hue light bulbs?

Each sentence has a mistake. Find it by chosing A B C or D 

In recent years, there  have been great increases in a number of engineers and scientists employed in American industries

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Nowadays, dozens of interventions are known that extend the lifespan of various living organisms ranging from yeast to mammals. They include chemical compounds, genetic interventions, and diets. Some targets of these interventions have been discovered. However, there is still no clear understanding of the systemic molecular mechanisms leading to lifespan extension. A group of scientists from Skoltech, Moscow State University and Harvard University decided to fill this gap and identify crucial molecular processes associated with longevity. To do so, they looked at the effects of various lifespan-extending interventions on the activity of genes in a mouse, a commonly used model organism closely related to humans. “In our lab, we subjected mice of different sexes and ages to 8 longevity interventions and analyzed gene expression changes induced by these treatments. After aggregating our data with the datasets published by other groups, we obtained gene activity profiles of 17 interventions. Although in general the effects produced by individual treatments turned out to be rather specific, a certain group of genes changed its expression in a similar way in response to different lifespan-extending interventions,” says the first author of the study, Alexander Tyshkovskiy. The scientists then applied the discovered biomarkers to search for other interventions with the same effect on their activity and, therefore, high potential for lifespan extension "Currently, we are validating these hits by testing their effect on the mouse lifespan. We hope that our biomarkers will significantly facilitate the search for new longevity interventions and help improve the healthspan and lifespan in rodents and, in the long term, in humans," says Alexander. 
4. The word “their” in paragraph 4 refers to _______