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: 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 2: Doctors believe there is better in this modern world of ours to try to prevent illnesses than to rely on medicines to cure them.

A. doctors

B. there is

C. of ours

D. to

Câu 3: By the turn of the century, most of the inventions that were to bring in all the comforts of modern living has already been thought of.

A. By the turn of

B. that

C. were to

D. has already been

Câu 4: 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 5: Parks which are found in downtown areas where office workers and store employees can enjoy their lunch hours sitting on the green grass in clean, fresh air.

A. which

B. employees

C. lunch hours sitting

D. fresh air

Câu 6: It is difficult to write rules that tell exactly when we should apologize, and it is not difficult to learn how to do it.

A. difficult

B. that

C. when

D. and