阅读以下教材原句，感悟体会并判断加颜色部分是什么从句。 1.Oliver believes that with a million pound bank note a man could survive a month in London. 2.I wonder，Mr Adams，if you’d mind us asking a few questions. 3.May we ask what you’re doing in this country and what your plans are? 4.I didn’t know whether I could survive until morning. 5.The fact is that I earned my passage by working as an unpaid hand，which accounts for my appearance. 6.That’s why we’ve given you the letter.