Câu hỏi: We’ll have to break the ice on the pond; otherwise the ducks .............. swim.

A. are not able to

B. will not be able to

C. would not be able to

D. would not have been able to

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: .............................. if I were you.

A. These wires would look dangerous

B. You should not touch these wires

C. I would not touch these wires

D. These wires were dangerous to you not to me

Câu 3: If it ............................... his wife’s money, he’d never be a director.

A. was

B. isn’t 

C. had had

D. were not for

Câu 4: Peasants spend most of their time on the ground, ...................... many speciesstay in trees at night.

A. if

B. though

C. because

D. as well as

Câu 5: The first hamburgers ..................... in Connecticut in 1895.

A. are sold 

B. were sold

C. sold

D. have been sold

Câu 6: Exactly .............. we can replace our soil disappearing through erosion is not known.

A. what

B. how

C. if

D. because