Câu hỏi: He had a new heart valve _______.

A. added

B. supplanted

C. improved

D. implanted

Câu 1: The problem of_______ in big cities, which stems from uncontrolled migration from rural areas.

A. overpopulation

B. decrease

C. increase

D. growth

Câu 2: Installing is firewall is one method of trying to protect against_______.

A. hackers

B. thiefs

C. robbers

D. crooks

Câu 3: The _______ by UN troops prevented fighting from breaking out.

A. participant

B. intervention

C. joiner

D. contestant

Câu 4: Some______ animals become tame if they get used to people.

A. wild

B. domestic

C. endangered

D. rare

Câu 5: We kept in _______for a while after college.

A. touch

B. pay

C. well

D. chose

Câu 6: Intelligent ___________ are widely used in many fields such as heavy industries, hospital medicine business, and the military.

A. machines

B. service

C. advisement

D. computers