H7N9 is a new kind of .
A Wechat (微信) is an invention __________ can help people talk to friends, share photo, ideas and feelings freely.
_____ of the water _____ polluted. We must try to protect our environment.
Please tell me______. I have some good news for him.
— You’re new here, ______?— Yes, I’m from Dujiangyan. I came here last week.
I am not sure if Tom____ home. If he________, I'll call you.