we must ask people not to cut down trees =we must -----people -------cutting down trees.

题目

we must ask people not to cut down trees =we must -----people -------cutting down trees.

答案

We must 【stop/ prevent 】people【from】cutting down trees.


祝你学习进步,更上一层楼! (*^__^*)
不明白的再问哟,请及时采纳,多谢!