给下列句子中的宾语从句加下划线,并将它们的引导词刷色（无实际意义、可以省略的加粗；有具体意义、不可省略的加下划线）
1,I said that I would be at your house at six o'clock,
2.I don't know when I'll finish.
3.My wife wants to know if Mary needs any help.
4.I don’t know why they didn’t come.
5.Tell me what you are talking about.
6.They thought that they could win a lot of money.