_____ concern about food safety seemsto be ______ subject that is being discussed all over the world.

One survey shows that large quantities of water ______wasted every year in China.

What are you going to do tonight— ______. If I am free, I may go to the cinema with my mother.

How about the pollution in the countryside —Luckily, it’s not as serious as_______ in the big cities.

Why does everyone like him—Because he always ______ a goodafter-dinner joke.