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: It ............... a lot last winter.

A. snows

B. has been snowing

C. snowed

D. snow

Câu 3: Annette spent a year long to search for scholarship; ................, she did not get positive result.

A. therefore

B. moreover

C. still

D. asa result

Câu 4: Louise was listening to the radio while she .................. the house.

A. is cleaning

B. was cleaning

C. had cleaned

D. will dean

Câu 5: The telephone .............. ten times before Patsy finally answered it.

A. rings

B. ringing

C. had rung

D. is ringing

Câu 6: Paul and Linda .............. us to their party last weekend.

A. was inviting

B. invited

C. had been inviting

D. will invite