Teachers should _____ their students to practice _____ English as much as possible.

The water in the river nearby will be dirtier than before if nothing __________.

There ________ lots of trees on both sides of this street.But now they are all gone.

— Is there a library in Gaochun? — Yes, a new library _______ and is now open to the public.

He liked playing cards very much. He didn’t want to stop _____meals, so he put meat between two pieces of bread.