1.I started learning English at the age of six.
2.The boy fell from the tree and hurt himself.
3.Please come with me.
4.I knew how to sing this song when I was four.(years old)
5.I heard her reading English a moment ago.
6.At that time ,I couldn't afford that car.
7.I did it just for fun.
8.Listen,somebody is knocking the door.
9.I am surprise that he is a police.(policeman)
10.I don't understand him at all.