Câu hỏi: Population growth rates vary among regions and even among countries within the same region.

A. fluctuate

B. stay unchanged

C. restrain

D. remain unstable

Câu 1: You can find the answer to almost any question in cyberspace.

A. require

B. comment

C. answer

D. sentence

Câu 2: Certain courses are compulsory; others are optional.

A. voluntary

B. free

C. pressure

D. mandatory

Câu 3: They started building the house in January.

A. begin

B. finish

C. commence

D. continue

Câu 4: Soon after it was born, the calf got up and tried to stand on its shaky legs.

A. appeared

B. died

C. joined

D. celebrated

Câu 5: The whole conference was totally disorganized - nobody knew what they were supposed to be doing.

A. someone

B. nothing

C. no one

D. something

Câu 6: It must be difficult to cope with three small children and a job.

A. easy

B. free

C. confusing

D. tricky