Câu hỏi: The developing of the submarine was hindered by the lack of a power source that could propel an underwater vessel.

A. developing

B. the

C. a power

D. could propel

Câu 1: The clerks who are happy to wait for their customer will get promoted soon.

A. clerks

B. wait for

C. customer

D. get promoted

Câu 2: Mary and her sister just bought two new winters coats at the clearance sale.

A. her sister

B. just bought

C. two new

D. winters

Câu 3: More Asian students than American counterparts agree that a husband is obliged tell his wife where he has been if he comes home late.

A. than

B. counterparts

C. tell

D. has been

Câu 4: Women nowadays have more free to participate in social activities.

A. nowadays

B. more

C. free

D. social

Câu 5: Ours brains are incredibly agile machines, and it's hard to think of anything they do more efficient than recognize face.

A. are

B. anything

C. efficient

D. recognize

Câu 6: The eastern bluebird is considered the most attractive bird native of North America by many bird-watchers.

A. bluebird

B. considered

C. native of

D. by