One learns a language by making mistakes and ________them.[ ]

Hearing his words ,I couldn’t decide or remain

The good thing about children is that they very easily to new environments.

We do our best to be careful and prevent bad things from happening，but most of us will________find ourselves in a situation where we or someone else needs help[ ]

rbon lifestyle is of great benefit toimprove the world environment, but the problem is difficult to _________．