Dãy số nào sau đây có giới hạn là +∞?

Khi nói về ảnh hưởng của các nhân tố môi trường đến quá trình quang hợp ở thực vật, phát biểu nào sau đây sai?

Hiến pháp Việt Nam có những đặc điểm nào?

Cho lăng trụ đứng \(A B C \cdot A^{\prime} B^{\prime} C^{\prime}\) có đáy ABC là tam giác đều cạnh \(a\). Gọi \(D\) là trung điểm cạnh BC . Biết \(A A^{\prime}=2 a\(, khoảng cách giữa hai đường thẳng \(A^{\prime} B\) và \(C^{\prime} D\) là:

Read the following passage about How Failures Led to Breakthroughs and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

Many important discoveries happened because of mistakes and unexpected accidents. Alexander Fleming found penicillin when he left his laboratory messy before going on holiday. After vacation, he saw mold growing on his experiment plate. Fleming noticed this mold killed bacteria around it very effectively. This fortunate accident later saved millions of lives around the world. Scientists call finding valuable things by chance "serendipity," which happens often in research.

The Post-it Note began as a mistake that seemed useless at first. In 1968, Spencer Silver tried making a strong glue for 3M company but created a weak one instead that didn't stick permanently. Nobody knew what to do with this disappointing result for several years. Then his colleague Arthur Fry realized this "failure" could make perfect bookmarks that wouldn't damage pages when removed. This weak adhesive eventually became one of the most popular office products worldwide, changing how people work.

In cooking, many favorite foods came from kitchen errors and quick substitutions. Ruth Wakefield invented chocolate chip cookies when she ran out of baker's chocolate and used broken pieces of semi-sweet chocolate instead. She thought they would melt completely in the dough, but they kept their shape during baking. Potato chips were created when chef George Crum made extremely thin potatoes to annoy a customer who repeatedly complained about thick fries. Surprisingly, the customer loved them and ordered more!

These fascinating stories teach us that mistakes can lead to new opportunities and unexpected innovations. Thomas Edison said about his many failed light bulb attempts, "I haven't failed. I've just found 10,000 ways that don't work." This positive attitude shows we should see errors as valuable learning chances. Smart people don't fear making mistakes in their work; they fear missing opportunities to learn from them and discover something amazing.

In which paragraph does the writer mention a failed attempt to create strong glue led to a useful product?

Read the passage carefully

1. Do you find yourself yawning all day at school? You probably need more sleep. However, it is not just how much sleep you get that is important. What you do before bedtime also has a huge effect on how you feel the next day. If you spend time chatting to someone on social media, or reading a book on your e- reader, you are not alone.

2. All devices' screens give out a large amount of blue light, which affects the body's production of the sleep hormone, melatonin, which can change your sleep patterns. So it is not just getting to sleep that becomes hard, but the quality of your sleep also suffers. The result is that you can wake up several times during the night, and have difficulty getting up in the morning.

3. Sleep is food for the brain, so not sleeping well can be a severe problem for anyone, especially for teenagers, because their brains are still developing. When you do not sleep well, it can be difficult to concentrate at school, which makes it harder to learn and get good grades. It can also affect your mood, making you feel sad or anxious. 

4. So, it is clear you should not use your phone before you go to sleep. Why not leave it in another room? Nothing on social media is so important that it cannot wait a few hours! You should rediscover paper books and enjoy feeling tired and sleepy before bedtime rather than wondering why your best friend has not liked your photo! How will you wake up? You do not have to use the alarm on your phone. Go and buy yourself an old-fashioned alarm clock! The negative effects that screen time is having on sleep have been in the news a lot recently, so manufacturers of smartphones and tablets have added a feature to the mobile devices that can help reduce these. Most new phones have a night-time setting that changes the colour of the screen so that it gives out less blue light. If you really cannot avoid going onto social media at bedtime, think about turning on this setting on your phone.

(Adapted from Prepare)

Which of the following can be the best title of the passage? 

Cho các cấp độ tổ chức cơ bản của thế giới sống như sau:

(1) Cơ thể.             (2) tế bào.         (3) quần thể.             (4) quần xã.            (5) hệ sinh thái.

Các cấp độ tổ chức sống trên được sắp xếp theo đúng nguyên tắc thứ bậc là:

Phát biểu nào sau đây về aldehyde, ketone là không đúng?

Một thang máy có khối lượng m=1 tấn đi xuống với gia tốc \(a = 1m/{s^2}\). Lấy\(g = 10m/{s^2}\). Trong thời gian 2s đầu tiên công của động cơ thang máy là

Xác định: Tiêu chí đầu tiên trong đánh giá công nghệ là gì?

Read the following passage about endangered languages and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questionsfrom 31 to 40.

[I] Social media has become a dominant force in modern communication, offering a range of benefits and challenges. [II] It has revolutionized the way people interact, share information, and even form relationships. [III] While these platforms offer opportunities for connection and expression, they also have their drawbacks. [IV] For instance, excessive use of social media has been linked to a range of negative effects, including mental health issues, social isolation, and decreased productivity. [V] However, when used responsibly, social media can also offer a variety of positive outcomes, such as the ability to stay connected with loved ones, network professionally, and access valuable information and resources.

One of the major benefits of social media is its ability to keep people connected. For example, individuals who live far apart can maintain close relationships through regular communication on these platforms. Social media also facilitates professional networking, allowing users to connect with potential employers or clients, and enabling companies to promote their products and services to a global audience. Additionally, platforms like Facebook, Twitter, and Instagram provide a space for people to share ideas, opinions, and creative work, fostering a sense of community and collaboration.

Despite these advantages, there are serious concerns about the negative impact of social media, particularly on mental health. Studies have shown that excessive social media use can contribute to feelings of anxiety, depression, and loneliness. This is often attributed to the unrealistic portrayals of life that are commonly shared on these platforms, leading to comparisons that can make individuals feel inadequate or left out. Furthermore, constant exposure to negative news or online bullying can exacerbate these feelings and contribute to long-term psychological stress.

Another issue with social media is its potential to distract people from their daily responsibilities. With notifications constantly popping up and endless streams of content to scroll through, individuals may find it difficult to focus on tasks such as work, school, or personal obligations. This can result in decreased productivity and a lack of attention to important matters.

Ultimately, the impact of social media depends on how it is used. If individuals are mindful of their usage patterns and take steps to limit their time on these platforms, they can enjoy the benefits of staying connected and informed without the negative consequences. Parents, educators, and mental health professionals can also play a role in helping young people develop healthy habits and manage their social media use effectively.

Which of the following best paraphrases the underlined sentence in paragraph 1?

“Social media has become a dominant force in modern communication."

Cho hàm số \(f\left( x \right)={{x}^{4}}+2{{x}^{2}}-3\). Tìm \(x\) để \({f}'\left( x \right)>0\).

Chọn ngẫu nhiên một số nguyên dương không lớn hơn 15. Hãy mô ta không gian mẫu trên?

Phương trình tổng quát của đường thẳng đi qua hai điểm A(3 ; -1) và B(1 ; 5) là:

Find the word which has a different sound in the part underlined.

Xác định ý đúng: Có mấy tiêu chí đánh giá sản phẩm?

Tập hợp nhiều tế bào cùng loại và cùng thực hiện một chức năng nhất định tạo thành yếu tố nào?

Trong nền kinh tế của nước ta, đâu là hoạt động cơ bản nhất đóng vai trò quyết định các hoạt động còn lại?

a. Naomi: I saw a program about coral bleaching. It looks so sad.

b. Naomi: That's terrible for all the fish and other animals that live there.

c. Leila: It happens when the water gets too warm. The coral loses its colour and can die.