Câu hỏi: I was very sad when the vet said he’d have to _____ Gertie, our lapdog.

A. put down

B. fell up to

C. pull through

D. wear off

Câu 1: The world’s biodiversity is declining at an unprecedented rate, which makes wildlife ________.

A. prosperous

B. vulnerable 

C. prefect

D. remained

Câu 2: The climate is not dry at all; in fact, they have ____ of water.

A. a redundancy

B. an abundance

C. a deficiency

D. a mixture

Câu 3: We were quite impressed by the ______ students who came up with the answer to our question almost instantly.

A. absent-minded

B. big-headed

C. quick-witted

D. bad-tempered

Câu 4: His work ______ new ground in the treatment of cancer. It is now giving many cancer victims hope of complete recovery.

A. broke

B. found

C. dug

D. uncovered

Câu 5: A _____ is a tube through which a person swimming just under the surface of the sea can breathe.

A. maneuver

B. photograph

C. volume

D. snorkel

Câu 6: A true relationship is thought to be a friendship that may__________through changes in the lives of the friends.

A. entail

B. remain

C. endure

D. continue