---______ to give the letter to Mr. Wang. It’s very important.  ---No, I won’t.

 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.

______ it is to listen to music when you are free. 

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

      your pets inside as much as you can when the weather is bad.