I’d like to help the homeless people in the earthquake. －You ________ join a volunteer group.

What _____ he doesn’t come to your party?—Well, I don’t mind.[ ]

I’m not good at English, my friend isn’t, ____.

What do you think of haze(雾霾)？ —- It ____ us we all must try to do something to stop the air pollution.

Liu Hua often helps her sister__________lessons.[ ]