Câu hỏi: Unless there had been a heavy storm, the climbers will not have died.

A. Unless

B. had been

C. heavy

D. will

Câu 1: Before went abroad, he had finished his English course at the English-speaking Center.

A. went

B. abroad

C. had finished

D. English-speaking

Câu 2: Ecologists are trying to preserve our environment for future generations by protecting the ozone layer, purifying the air, and have planted the trees that have been cut down.

A. to preserve

B. for

C. the ozone layer

D. have planted

Câu 3: This apprentice has spent two weeks to work on that new machine.

A. has spent

B. to work

C. on

D. new machine

Câu 4: Narcissus, a character in mythology, gazed at his own image in a pool so ardently that he fell into itself and downed.

A. a character in mythology

B. his own

C. that

D. into itself

Câu 5: The master of ceremonies announced in a loud and clear voice and told that the dinner would be late due to unforseen circumstances.

A. of ceremonies

B. and told

C. would be

D. due to

Câu 6: What happened in New York were a reaction from city workers, including firemen and policemen who had been laid off from their jobs.

A. What happened

B. were

C. including

D. their