Câu hỏi: I_______ George on my way home.

A. dropped in on

B. gear up for

C. pair up with

D. look back on

Câu 1: We all regard pollution as a.......... matter to human beings.

A. solemn 

B. great

C. serious 

D. huge

Câu 2: The_______ of living here, of course, is that it is expensive.

A. glorious

B. athletic

C. strategy

D. downside

Câu 3: The society was set up to______ endangered species from extinction.

A. prevent

B. distinguish

C. preserve

D. survive

Câu 4: This_______disease caused a lot of complications during the treatment procedure.

A. situation

B. difficult

C. life-threatening

D. weak

Câu 5: The waste water from bath, showers, sinks and_______, and rainwater can be collected in a tank.

A. linguistic

B. official

C. dishwasher

D. operate

Câu 6: He had a new heart valve _______.

A. added

B. supplanted

C. improved

D. implanted