Câu hỏi: My teacher is very strict and he always makes us to finish all the exercises before leaving school.

A. is

B. strict

C. to finish

D. leaving school

Câu 1: 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

Câu 2: If you take the train, it would be much more convenient.

A. if

B. the train

C. would be

D. much

Câu 3: It is very difficult for her to prevent him for smoking in her house.

A. very

B. for 

C. prevent 

D. for smoking

Câu 4: 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 5: My elder sisters, both of them were doctors, said they were too busy to pick me up.

A. elder

B. both of them

C. too busy 

D. to pick

Câu 6: 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