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

A. for

B. at

C. in

D. on

Câu 1: Smoking is harmful _____________ our health.

A. to

B. by

C. against

D. with

Câu 2: Our study is very important____________ our future and useful_____________ our country.

A. for/ for

B. to/ to

C. for/ to

D. to/ for

Câu 3: He wore a hat, which made him look _______________ a spy.

A. like

B. up

C. after

D. back

Câu 4: We might need more food, depending ____ how many people turn up.

A. for

B. on

C. at

D. with

Câu 5: A sign warned motorists ______ dangers.

A. of

B. for

C. about

D. a and c

Câu 6: Mary always take good care__________ her children.

A. off

B. of

C. by

D. with