Underline the mistakes and rewrite the correct sentences :
1. How many does it cost to send this letter to China
2. Who will give care of the house while we are away?
3. The post office sells phone card apart of stamps
4. Because we have to be there in a hurry , we better take a taxi
5.When I am ill, my mother looks at me
6. Students have work hard at school and at home
7.When I first saw her, I thought she looked happily
8. What clever brother you have !