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

A. are sold 

B. were sold

C. sold

D. have been sold

Câu 1: 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 2: Hamburgers ...................... favorite in America in the early century.

A. became

B. becomes

C. has become

D. was become

Câu 3: Take John's address with you, ................... you have time to see him whenyou’re in London.

A. if

B. unless

C. in case

D. so long as

Câu 4: Exactly .............. we can replace our soil disappearing through erosion is not known.

A. what

B. how

C. if

D. because

Câu 5: If you’re not coming, ............................

A. we had not been in such trouble

B. you may need to tell me

C. we’d never met

D. you’d be so lucky

Câu 6: ......................... any difficulty operating the machine, do not hesitate totelephone our service department.

A. Should you have

B. If you should

C. In case you have

D. Unless you have