Question

We must do something to ________ factories ________ waste water into the river b

We must do something to ________ factories ________ waste water into the river before it is cleaned.
A. stop; pouring
B. prevent; to pour
C. keep; pouring
D. stop; to pour

Answer 1

答案A
stop/ prevent sb. /sth. (from) doing sth. 阻止某人／物做某事，from可以省略；keep sb. /sth. from doing也是"阻止某人／物或某事"，但是from不可省略。"