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

A. restrain

B. stay unchanged

C. remain unstable

D. fluctuate

Câu 1: He is over the moon about his examination result.

A. stressed

B. very sad

C. very happy

D. satisfied

Câu 2: He is among wealthy members of the golf club.

A. adroit

B. affluent

C. adjacent

D. poor

Câu 3: A chronic lack of sleep may make us irritable and reduces our motivation to work.

A. uncomfortable

B. responsive

C. calm

D. miserable

Câu 4: We'd better speed up if we want to get there in time.

A. slow down

B. turn down

C. put down

D. lie down

Câu 5: With her sophiscated tastes, the singer has become an omnipresent icon of style and beauty.

A. oblivious

B. controversial

C. ubiquitous

D. unknown

Câu 6: Solar energy is not only plentiful but also infinite.

A. without limit

B. boundless

C. limited

D. indefinite