Cho các chất sau: toluene, etilen, vinyl clorua, striren, vinyl axetilen, etanal, isoprene, propilen, axit axetic. Số các chất làm mất màu dung dịch Brom là

A.5

B. 7

C. 6

D. 8

Read the passage and mark A, B, C or D to indicate the correct answer to each of the questions.

 We find that bright children are rarely held back by mixed-ability teaching. On the contrary, both their knowledge and experience are enriched. We feel that there are many disadvantages in streaming pupils. It does not take into account the fact that children develop at different rates. It can have a bad effect on both the bright and the not-so-bright child. After all, it can be quite discouraging to be at the bottom of the top grade!

 Besides, it is rather unreal to grade people just according to their intellectual ability. This is only one aspect of their total personality. We are concerned to develop the abilities of all our pupils to the full, not just their academic ability. We also value personal qualities and social skills, and we find that mixed-ability teaching contributes to all these aspects of learning.

 In our classroom, we work in various ways. The pupils often work in groups; this gives them the opportunity to learn to co-operate, to share, and to develop leadership skills. They also learn how to cope with the personal problems as well as learning how to think, to make decisions, to analyze and evaluate, to communicate effectively. The pupils learn from each other as well as from the teachers.

 Sometimes the pupils work in pairs; sometimes the work on individual tasks and assignments, they can do this at their own speed. They also have some formal class teaching when this is appropriate. We encourage our pupils to use the library, and we teach them the skills they need in order to do this effectively. An advanced pupil can do advanced works; it does not matter what age the child is. We expect our pupils to do their best, not their least, and we give them every encouragement to attain this goal.
Question:According to the passage, “streaming pupils” ______

A. is the act of putting pupils into class according to their academic abilities

B. aims at enriching both their knowledge and experience

C. is quite discouraging

D. will help the pupils learn best

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 questions.

The first two decades of this century were dominated by the microbe hunters. These hunters had tracked down one after another of the microbes responsible for the most dreaded scourges of many centuries: tuberculosis, cholera, diphtheria. But there remained some terrible diseases for which no microbe could be incriminated: scurvy, pellagra, rickets, beriberi. Then it was discovered that these diseases were caused by the lack of vitamins, a trace substance in the diet. The diseases could be prevented or cured by consuming foods that contained the vitamins. And so in the decades of the 1920's and 1930's, nutrition became a science and the vitamin hunters replaced the microbe hunters.

In the 1940's and 1950's, biochemists strived to learn why each of the vitamins was essential for health. They discovered that key enzymes in metabolism depend on one or another of the vitamins as coenzymes to perform the chemistry that provides cells with energy for growth and function. Now, these enzyme hunters occupied center stage.

You are aware that the enzyme hunters have been replaced by a new breed of hunters who are tracking genes - the blueprints for each of the enzymes - and are discovering the defective genes that cause inherited diseases - diabetes, cystic fibrosis. These gene hunters, or genetic engineers, use recombinant DNA technology to identify and clone genes and introduce them into bacterial cells and plants to create factories for the massive production of hormones and vaccines for medicine and for better crops for agriculture. Biotechnology has become a multibilliondollar industry.

In view of the inexorable progress in science, we can expect that the gene hunters will be replaced in the spotlight. When and by whom? Which kind of hunter will dominate the scene in the last decade of our waning century and in the early decades of the next? I wonder whether the hunters who will occupy the spotlight will be neurobiologists who apply the techniques of the enzyme and gene hunters to the funtions of the brain. What to call them? The head hunters. I will return to them later.
Question:The author implies that the most important medical research topic of the future will be

A. the functions of the brain

B. inherited diseases

C. the operation of vitamins

D. the structure of genes

Thời gian trước đây, theo kinh nghiệm thâm canh lúa nước, sau mỗi vụ mùa vụ, nhà nông thường hay đốt đồng (đốt gốc rạ còn lại trên đồng lúa sau thu hoạch). Theo cách thức canh tác đó, việc đồng giúp

A. cung cấp thêm cho cánh đồng ở mùa vụ sau một lượng đạm dưới dạng  N 2 .

B. cung cấp thêm cho cánh đồng ở mùa vụ sau một lượng kali dưới dạng K 2 CO 3 .

C. loại bỏ dư lượng thuốc trừ sâu cho cánh đồng để chuẩn bị mùa vụ mới.

D. làm sạch phần lúa bị rơi rụng khi thu hoạch để chuẩn bị gieo giống mới.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

Although both of them (A) are trying (B) to get (C) the scholarship, she has the highest (D) grades.

A. of them

B. are trying

C. to get

D. highest 

Protein không thực hiện chức năng

A. điều hoà các quá trình sinh lý 

B. xúc tác các phản ứng sinh hoá.

C. bảo vệ tế bào và cơ thể

D. tích lũy thông tin di truyền.

Khi nói về cơ chế dịch mã ở sinh vật nhân thực, có bao nhiêu định sau đây là đúng?

(1). Khi dịch mã, ribôxôm chuyển dịch theo chiều 5’→3’ trên phân tử mARN.

(2) Khi dịch mã, ribôxôm chuyển dịch theo chiều 3’ →5’ trên phân tử nhân tử mARN

(3) Trong cùng một thời điểm có thể có nhiều ribôxôm tham gia dịch mã trên một phân tử mARN. .

(4). Axit amin mở đầu trong quá trình dich mã là mêtiônin.

A. 3

B. 2

C. 1

D. 4