Câu hỏi: Exactly .............. we can replace our soil disappearing through erosion is not known.

A. what

B. how

C. if

D. because

Câu 1: If you ................... a pet bird, you’ll have to buy a cage, too.

A. buy

B. will buy

C. bought

D. had bought

Câu 2: Hamburgers ...................... favorite in America in the early century.

A. became

B. becomes

C. has become

D. was become

Câu 3: The first hamburgers ..................... in Connecticut in 1895.

A. are sold 

B. were sold

C. sold

D. have been sold

Câu 4: ...................... we would have lost the match.

A. Unless the goal-keeper had played well

B. But for the goal-keeper’s heroics

C. If it were not for the goal-keeper

D. Because the goal-keeper was good

Câu 5: Applicants ................ send in their CVs.

A. asked

B. ask to 

C. are asked to

D. asked to

Câu 6: If you’re too ill to come,     ......................................

A. I’ll come over and see you

B. I wouldn’t have done all this for you

C. I asked someone else

D. I’d have come to see you