Câu hỏi: Ecologists are trying to preserve our environment for future generations by protecting the ozone layer, purifying the air, and have planted the trees that have been cut down.

A. to preserve

B. for

C. the ozone layer

D. have planted

Câu 1: Please tell us the reason when he left without saying goodbye.

A. tell

B. when

C. left

D. saying

Câu 2: It has ever been told that teaching is one of the more noble careers.

A. has ever been

B. is

C. the 

D. more noble

Câu 3: Teddy Roosevelt demonstrated his competitive spirit and tireless energy in 1905 whenever he led the Rough Riders up San Juan Hill.

A. demonstrated

B. competitive

C. whenever

D. he

Câu 4: In spite of my father is old , he gets up early and does morning exercise.

A. In spite of

B. is

C. gets up

D. does morning exercise

Câu 5: Has the government made a decide to ban the use of chemical weapon yet?

A. has

B. decide

C. to ban

D. use

Câu 6: Thanks for the liberation of women, women can now take part in social activities.

A. thanks for

B. liberation of

C. can

D. take part in