Câu hỏi: He had a new heart valve _______.

A. added

B. supplanted

C. improved

D. implanted

Câu 1: Some______ animals become tame if they get used to people.

A. wild

B. domestic

C. endangered

D. rare

Câu 2: You need to_______ the numbers properly in a column.

A. align

B. check

C. draw

D. write

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

A. participant

B. intervention

C. joiner

D. contestant

Câu 4: In military, A.I. robots are used to _______ dangerous environments containing explosives or contaminated by nuclear weapons.

A. change

B. explore

C. fix

D. borrow

Câu 5: She finally achieved her_______ of visiting the USA.

A. target

B. objective

C. desires

D. ambition

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

A. solemn 

B. great

C. serious 

D. huge