Cấu trúc lặp với số lần chưa biết trước có dạng như thế nào?

Chất nào không được dùng làm nguyên liệu cho quá trình chuyển hóa các chất trong tế bào?

Trong khai triển nhị thức \((a + 2)^{n + 6}\) (n ∈ ℕ). Có tất cả 17 số hạng. Vậy n bằng

Hình ảnh sau đây cho thấy cây bị bệnh gì?

Read the following passage about education in Nepal 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 31 to 40. 

Fashion in the 1960s reflected the cultural and political upheaval of the time. The hippie and counterculture movement gave rise to accessories like Pocahontas-style headbands and medallions worn around the neck. Hippies wore long, loosely fitting clothing, often in natural fabrics. Hemlines rose as Mary Quant popularized the miniskirt and hot pants in her lines for JC Penney. And mod fashion, with brightly colored space-age geometric patterns, shift dresses and colored tights became the mainstream. Both miniskirts and mod-shift dresses were worn with knee-high go-go boots.

[A] During the 1970s, the loose-fitting hippie clothes of the prior decade gave way to exotic fabrics and bell-bottom jeans for men and women. Hemlines continued to rise and hot pants continued their popularity, reflecting the flashy style of the decade. However, the 1970s also saw the popularity of a longer hemline, from mid-calf to ankle-length. [B] Women wore peasant-style clothing, especially blouses with off-the-shoulder necklines and lace trim, with their jeans or skirts. [C] Disco fashion emerged, featuring bright patterns and tightly fitting clothing meant to show off the body. Platform shoes elevated their wearer, male or female, anywhere from two to four inches or more. [D]

The 1980s saw another fashion upheaval. Angst-ridden punks wore Dr. Marten and steel-toed army boots, chains, tartan patterns, and bondage pants. Punks focused more on their hair during this period, dying, teasing and chopping their hair into asymmetric styles that seemed to defy gravity. Women—and men—experimented with heavy eyeliner in a variety of colors. Women wore neon colors, jelly shoes, tight jeans, leggings, leg warmers and oversized sweatshirts. Menswear-inspired looks also became popular for both sexes. Men wore ‘power suits,’ named so for their price, which made these suits a reflection of the wealth of the wearer. Women’s jackets featured big shoulder pads that made the shoulders appear higher and larger, similar to the male silhouette.

1990’s fashion was far more subdued than the garish, wild styles of the 1980s. Bands like Nirvana influenced the grunge look, which featured rock-concert tee shirts under plaid flannel shirts, jeans and long, greasy hair. Overalls were worn by both sexes, either with one or both shoulder straps unhooked. The punk style of the 1870s and 1980s evolved into the goth fashion trend, which featured black clothing, black boots and studded bracelets in the style of bands like Nine Inch Nails and Marilyn Manson.

The word “their” in paragraph 2 refers to ______.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions

[I] A newborn baby can see, hear and feel. By the age of five, a child can talk, ride a bike and invent imaginary friends. How does this development happen? [II]We don't understand the way language, thinking and planning develop very well. [III]Now scientists are using new technology to ‘see’ into children's brains. And they are discovering new information about the way a baby's brain develops. [IV]

A study in 2010 showed that children who were afforded more focus often gained an edge in IQ. The brain of a newborn infant contains nearly a hundred billion neurons. This number is comparable to that of an adult's brain. As they mature, an infant assimilates information through the sensory modalities of sight, hearing, smell, taste, and touch. This information fosters intricate connections between different regions of the brain. By the age of three, there are approximately a hundred trillion synaptic connections.

One experiment looked at images of babies' brains while they were listening to different sounds. The sounds were in different sequences. For example, one sequence was mu-ba-ba. This is the pattern ‘A-B-B’. Another sequence was mu-ba-ge. This is the pattern ‘A-B-C’. The images showed that the part of the brain responsible for speech was more active during ‘A-B-B’ patterns. This shows that babies can tell the difference between different patterns. This experiment is interesting because sequences of words are important to grammar and meaning. Compare two sentences with the same words in a different order: ‘John killed the bear’ is very different from ‘The bear killed John.’ So babies are starting to learn grammatical rules from the beginning of life.

Researchers also know that babies need to hear a lot of language in order to understand grammar rules. But there is a big difference between listening to television, audiobooks or the internet, and interacting with people. One study compared two groups of nine-month-old American babies. One group watched videos of Mandarin Chinese sounds. In the other group, people spoke the same sounds to the babies. The test results showed that the second group could recognize different sounds, however, the first group learned nothing. The scientist, Patricia Kuhl, said this result was very surprising. It suggests that social experience is essential to successful brain development in babies.

The word “This” in paragraph 3 refers to:

Người ta tiến hành khảo sát các yếu tố ảnh hưởng đến lượng khí CO₂ thu được trong một khoảng thời gian xác định từ phản ứng giữa đá vôi với dung dịch HCl 1M. Trong điều kiện thí nghiệm nào dưới đây, lượng khí CO₂ thu được là lớn nhất?

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.

Which of the following is NOT TRUE according to the passage?  

Đồ thị hàm số \(y = f\left( x \right) = \left\{ \begin{array}{l}2x + 3{\rm{ }}\,\,\,khi{\rm{ }}x \le 2\\{x^2} - 3{\rm{ }}\,\,\,khi{\rm{ }}x > 2\end{array} \right.\) đi qua điểm có tọa độ nào sau đây?

Các doanh nghiệp trong nước và ngoài nước cạnh tranh đầu tư sản phẩm trứng gia cầm. Doanh nghiệp T đã nỗ lực chú trọng đầu tư công nghệ sản xuất nhằm nâng cao chất lượng sản phẩm của mình trên thị trường, đầu tư dây chuyền kĩ thuật xử lí trứng gà bằng ozon và tia cực tím trước khi đóng hộp, tạo ra sản phẩm trứng gà tươi, cung ứng số lượng lớn trứng gà tươi ăn liền tại hệ thống siêu thị trong nước và kí kết nhiều đơn hàng xuất khẩu sang các quốc gia và vùng lãnh thổ. Nhờ nắm bắt được nhu cầu của khách hàng, doanh thu của doanh nghiệp T không ngừng tăng lên và khẳng định được vị thế của mình trên thị trường. Xác định những tác động từ cơ chế thị trường đến doanh nghiệp T.

Nhận định nào sau đây không phản ánh đúng nguyên nhân dẫn đến cạnh tranh kinh tế?

Phát triển đáp ứng được nhu cầu của hiện tại mà không làm tổn hại đến khả năng đáp ứng nhu cầu đó của các thế hệ tương lai gọi là gì?

Ngân sách nhà nước có các đặc điểm chủ yếu nào?

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