我不知道他是個教師還是別的什么。

　　I don't know if he's a teacher or what.

　　我不知道我一陣大哭持續了多久。

　　I don't know how long my crying jag lasted.

　　太好了。我不知道怎樣才能報答你。

　　It was very kind. I don't know how I can ever repay you.

　　我不知道你怎么能忍受那樣的噪音！

　　I don't know how you tolerate that noise!

　　我不知道。我沒有參與那場爭論。

　　I don't know. I wasn't in on that particular argument.