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

A. very

B. for 

C. prevent 

D. for smoking

Câu 1: 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 2: My father asked me where had I gone the night before.

A. the

B. asked me

C. had I

D. before

Câu 3: The harder he tried, the worst he danced before the large audience.

A. worst

B. the

C. before

D. tried

Câu 4: Having finished his tem paper before the deadline, it was delivered to professor before the class.

A. having finished

B. before

C. it was delivered

D. before

Câu 5: 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 6: Each of the members of the group were made to write a report every week.

A. were

B. members

C. to write

D. week