It’s hard to keep the house _____ with three kids.

Tom speaks Chinese very well. Who teaches him?— He studies by __________.

Must I finish my composition (作文) right now?－No, you _______.You can hand it in tomorrow.

The hazy weather has ________ for almost a week in North China. —Yes, and the government has tried to solve it.

I have to study _____a test.[ ]