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: I .............. Michael for years.

A. have known

B. know

C. knowing

D. was known

Câu 2: Mr. and Mrs. Wilson .............. some disputes with their neighbors.

A. having

B. have been having

C. have having

D. have been had

Câu 3: Babies ................ when they are hungry.

A. cry

B. are crying

C. have been crying

D. cries

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

A. am getting

B. get

C. have gotten

D. was getting

Câu 5: We always...................... a present to Elsa on her birthday.

A. are taking

B. taking

C. take

D. are taken

Câu 6: The Smiths are eating less and exercising more; ..............., they can keep their weight down and stay in shape.

A. Consequently

B. also

C. nevertheless

D. otherwise