Câu hỏi: He had a new heart valve _______.

A. added

B. supplanted

C. improved

D. implanted

Câu 1: I’m trying to_______ the amount of sugar I eat.

A. cut down on

B. bear out

C. bring in

D. team up with

Câu 2: The society was set up to______ endangered species from extinction.

A. prevent

B. distinguish

C. preserve

D. survive

Câu 3: The factory was fined for______ chemicals into the river.

A. dumping

B. discharging

C. producing

D. exposing

Câu 4: Installing is firewall is one method of trying to protect against_______.

A. hackers

B. thiefs

C. robbers

D. crooks

Câu 5: The_______ of living here, of course, is that it is expensive.

A. glorious

B. athletic

C. strategy

D. downside

Câu 6: We all regard pollution as a.......... matter to human beings.

A. solemn 

B. great

C. serious 

D. huge