Câu hỏi: The boy found a wallet in the street, and then he ...... to return it to the loser.

A. tried

B. had tried

C. was trying

D. had been trying

Câu 1: I would like to send these letters …………………..air mail.

A. in

B. with

C. by

D. over

Câu 2: The two children blamed each other ...... the window.

A. to break

B. breaking

C. for breaking

D. having broken

Câu 3: The ...... friendly products are designed not to harm the natural environment.

A. environment

B. environmental

C. environmentally

D. environmentalism

Câu 4: The campaign will hopefully ensure the survival ...... the tiger.

A. of

B. for

C. to

D. on

Câu 5: The panda's ...... habitat is the bamboo forest.

A. nature

B. natural

C. naturalized

D. naturally

Câu 6: Deforestation _________ destroying Earth’s plant and animal variety.

A. are

B. be

C. is

D. being