Câu hỏi: The old drainage pipelines must be maintained; ................, leakage will be unavoidable.

A. therefore

B. similarly 

C. on the contrary

D. otherwise

Câu 1: We .............. to the baseball game when it started to rain.

A. are driving

B. drives

C. driven

D. were driving

Câu 2: Some people are using motorbikes for transportation; ....................., others are taking publicvehicles to get to their destination.

A. hence

B. otherwise

C. therefore

D. besides

Câu 3: Mr. and Mrs. Wilson .............. some disputes with their neighbors.

A. having

B. have been having

C. have having

D. have been had

Câu 4: I ................. the house before you called.

A. leave

B. am leaving

C. had left

D. had been leaving

Câu 5: Barbara .................. that package to you tomorrow morning.

A. deliver

B. is going to deliver

C. are going to deliver

D. delivering

Câu 6: By next month, I ...................... at this company for a year.

A. will work

B. will be working

C. will have been working

D. am going to work