As a teacher, you should not _______ the students from asking questions in class.

With the help of the government , a large number of people ---_______ after the flood in 1991.

This river is so big that it is impossible to build a _______under it without modern technology.

If you have any problems during your study here,please do not _______ to call me for help

Whathesaidinthemeeting_______everybodypresent.