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 always...................... a present to Elsa on her birthday.

A. are taking

B. taking

C. take

D. are taken

Câu 2: We ....................... in the plane for hours when it finally, took off.

A. had been sitting

B. have sat

C. will be sitting

D. will sit

Câu 3: The telephone .............. ten times before Patsy finally answered it.

A. rings

B. ringing

C. had rung

D. is ringing

Câu 4: The new project received a lot of financial assistance from the WTO; ..............., it could easilybe approved by the authority.

A. thus

B. on the other hand

C. on the contrary

D. inaddition

Câu 5: I don't want to go outside today because it ....................

A. rain

B. rains

C. is raining

D. is rain

Câu 6: Annette spent a year long to search for scholarship; ................, she did not get positive result.

A. therefore

B. moreover

C. still

D. asa result