48课
dentist always ask questions when it is impossible for you to answer这个是时间状语从句
my tongue was busy searching out the hole where the toothe had been这个是定语从句
when dentist at last removed the cotton wool from my mouth,.这个是时间状语从句
49课
tired of sleeping on the floor,a young man .原因状语,但是不能叫从句,前面省略了being
另外,49课太多状语从句了,不好一一列出,那几个有when,because,although,after连接的句子,中间用逗号隔开,后面连一个完整的句子,句末用句号的,都是状语从句