Câu hỏi: Proteins are made up of folded irregularly chains, the links of which are amino acids.

A. made up of

B. folded irregularly

C. the links

D. which

Câu 1: The world is becoming more industrialized and the number of animal species that have become extinct have increased.

A. industrialized

B. species

C. extinct 

D. have

Câu 2: Tom said that he was trying to carry out some campaigns to protect environment and will encourage others to do so.

A. he was trying

B. some

C. campaigns

D. will

Câu 3: My pen has very few ink in it, so could you give me some

A. has 

B. few ink

C. could

D. some

Câu 4: Students suppose to read all the questions carefully and find out the answers to them.

A. suppose

B. all the

C. all the questions

D. them

Câu 5: My sister told me that she had met my teacher at the supermarket yesterday.

A. My sister told

B. had met

C. at the supermarket 

D. yesterday

Câu 6: A smile can be observed, described, and reliably identify, it can also be elicited and manipulated under experimental conditions.

A. identify

B. experimental

C. can also

D. A smile