Câu hỏi: How long have they been working _____________ the company?

A. for

B. at

C. in

D. on

Câu 1: It was very nice__________ him to give me a lift.

A. of

B. by

C. to

D. on

Câu 2: Ken prefers Chinese food________ French food.

A. to

B. or

C. and

D. with

Câu 3: You should make use___________ the books you have.

A. of

B. by

C. to

D. up

Câu 4: Smoking is harmful _____________ our health.

A. to

B. by

C. against

D. with

Câu 5: The pens made___________ plastic are very cheap.

A. by

B. with

C. of

D. to

Câu 6: If you look __________ the book, you can find what you need.

A. through 

B. up

C. after

D. by