It ’s our duty topeopletoo many trees.A. stop; cutting downB. prevent to cut downC. keep

问题补充：

It ’s our duty topeopletoo many trees.

A. stop; cutting down

B. prevent, to cut down

C. keep; cutting down

D. make; cut down

答案：

(答案→)A. stop; cutting down

B. prevent, to cut down

C. keep; cutting down

D. make; cut down

解析：stop/ prevent sb from doing sth,阻止某人做某事,from可省略。Keep sb from doing sth,from不可省。因此选A。