Imagine how excited we were ____ that our schoolmates had been admitted to some famous universities.

 That hazy（雾霾）weather has hit 104 cities in middle-east China lately makes citizens well aware of ______a terrible problem China is faced with.

—I’m leaving now.—______ you turn off the lights and the computer.

It’s a fine day. Let’s go swimming, ＿＿＿＿＿? 

 ____ the boy is to learn to talk.