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

A. is cleaning

B. was cleaning

C. had cleaned

D. will dean

Câu 2: The store ..................... two sales so far this year.

A. is having

B. has been having

C. has

D. has had

Câu 3: 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

Câu 4: I ............... on the bus when I dropped my wallet.

A. am getting

B. get

C. have gotten

D. was getting

Câu 5: I .............. Michael for years.

A. have known

B. know

C. knowing

D. was known

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