22. Trees are cut down and used to make paper and some wood –………..products.
A. relate B. relating C. related D. relates
23. We don’t want to leave the rubbish …………. because it is not good for the environment.
A. behind B. below B. beneath D. before
24. They learn ………….. to help save wild animals in the local research centre.
A. which B. where C. how D. who
25. One thing every citizen should do is to ………… littering on the beach or the street.
A. increase
B. punish
C. promise
D. avoid