8. I’ve done my best. 我已尽力了。
9. Is that so? 真是那样吗?
常用在一个人听了一件事后表示惊讶、怀疑。
10. Don’t play games with me!别跟我耍花招!
11. I don’t know for sure.我不确切知道。
Stranger: Could you tell me how to get to the town hall?
Tom: I don’t know for sure. Maybe you could ask the policeman over there.