Read the following passage on commuting, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 51 to 60.

Many folk cures which have been around for centuries may be more therapeutic than previously suspected. A case in point is that of penicillin Alexander Fleming did not just randomly choose cheese molds to study when he discovered this very important bacteria-killing substance. Moldy cheese was frequently given to patients as a remedy for illness at one time Fleming just isolated what it was about the cheese which cured the patients.

In parts of South America, a powder obtained from grinding sugar cane is used for healing infections in wounds and ulcers. This usage may date back to pre-Colombian times. Experiments carried out on several hundred patients indicate that ordinary sugar in high concentrations is lethal to bacteria. Its suction effect eliminates dead cells and it generates a glasslike layer which protects the wound and ensures healing.

Another example of folk medicine which scientists are investigating is that of Arab fishermen who rub their wounds with a venomous catfish to quicken healing. This catfish excretes a gellike slime which scientist found to contain antibiotics coagulant that helps close injured blood vessels, anti-inflammatory agents, and a chemical that directs production of a glue-like material that aids healing.

It is hoped that by documenting these folk remedies and experimenting to see if results are indeed beneficial, an analysis of the substance be made, and synthetic substances be developed for human consumption.

The word "consumption" in the last paragraph is closest in meaning to_________ 

A. utilisation

B.destruction

C.experimentation

D. manipulation

Thủy phân m gam saccarozo trong môi trường axit với hiệu suất 80% thu được dung dịch X. Trung hòa X bằng NaOH thu được dung dịch Y. Y hòa tan tối đa 17,64 gam  Cu OH 2 . Giá trị của m gần nhất với

A. 49.

B. 77.

C. 68.

D. 61.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer for 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 classrooms, 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 personal problems as well as learning how to think, to make decisions, to analyze and evaluate, and to communicate effectively. The pupils learn from each other as well as from the teachers.

Sometimes the pupils work in pairs; sometimes they work on individual tasks and assignments, and 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 work; 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.

According to the passage, which of the following is NOT TRUE?

A. It’s not good for a bright child to find out that he performs worst in a mixed-ability class.

B. Development of pupils as individuals is not the aim of group work.

C.  Pupils cannot develop in the best way if they are streamed into classes of different intellectual abilities.

D. There is no fixed method in teaching pupils to develop themselves to the full.

Hòa tan hết 3,264 gam hỗn hợp X gồm FeS₂, FeS, Fe, CuS và Cu trong 600ml dung dịch HNO₃ 1M đung nóng, sau khi kết thúc các phản ứng thu được dung dịch Y và 1,8816 lít (đktc) một chất khí thoát ra. Cho Y tác dụng với lượng dư dung dịch BaCl₂ thu được 5,592 gam kết tủa. Mặt khác, dung dịch Y có thể hòa tan tối đa m gam Fe. Biết trong quá trình trên, sản phẩm khử duy nhất của N⁺⁵ là NO. Giá trị của m là

A. 9,760

B. 9,120

C. 11,712

D. 11,256

Hiđro hoá cao su Buna thu được một polime có chứa 11,765% hiđro về khối lượng, trung bình một phân tử H₂ phản ứng được với k mắt xích trong mạch cao su. Giá trị của k là :

A. 4

B. 3.

C. 2

D. 5

Ổ sinh thái là:

A. một không gian sinh thái mà ở đó tất cả các nhân tố sinh thái quy định sự tồn tại và phát triển của loài.

B. một khoảng không gian giới hạn sinh thái của loài.

C. nơi ở của loài, sinh sản của loài.

D. nơi sinh vật kiếm ăn, và những giới hạn sinh thái của loài.

Cho các phát biểu sau:

(1) Trong một phân tử tetrapeptit mạch hở có 4 liên kết peptit

(2) Dung dịch lysin làm xanh quỳ tím

(3) Anilin tác dụng với nước brom tạo thành kết tủa trắng

(4) Peptit Gly-Ala có phản ứng màu biure với Cu(OH)₂

(5) Thủy phân hoàn toàn protein đơn giản thu được các a-aminoaxit

(6) Các hợp chất peptit kém bền trong môi trường bazơ nhưng bền trong môi trường axit

Sos phát biểu đúng là:

A. 5

B. 4

C. 3

D. 2