Câu hỏi: Jason’s professor had him to rewrite his thesis many times before allowing him to hand it in.

A. had

B. to rewrite

C. many times

D. allowing

Câu 1: Unless there had been a heavy storm, the climbers will not have died.

A. Unless

B. had been

C. heavy

D. will

Câu 2: 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 3: 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 4: The chief of police demanded from his assistants an orderly investigation, a well-written report, and that they work hard.

A. The chief

B. from

C. orderly

D. that they work hard

Câu 5: Conservation is the safeguarding and preservation of nature resources.

A. is

B. safeguarding

C. preservation

D. nature

Câu 6: 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