Those who have ________ floods and sandstorms know the importance of environmental protection.

— Do you often visit your grandparents?　— Mmm… ________ , I’m afraid. I usually phone them.

It shows that a knowledge of first aid can ______________.

We trust you ; only you can          him to give up smoking .

A thunderstorm is likely to come. Let’s hurry up so as not to __________ it.