-How amazing it is that astronauts are exploring outer space!
-It’s a challenge, I guess, man against nature.
A. of B. for C. by D. about
When she first arrived in China, she wondered what the future might have_______ for her, but now all her worries are gone.
A. in need B. in time C. in preparation D. in store
Are you ready for Spain?
Yes. 1 want the girls to experience that______they are young.
A. while B. until C. if D. before
Scientists are convinced the positive effect of laughter physical and mental health.
A. of; at B. by; in C. of; on D. on; at
Leaves are found on all kinds of trees, but they differ greatly size and shape.
A. on B. from C. by D. in
If you really have to leave during the meeting, you’d better leave ____ the back door.
A. for B. by C. across D. out
