这些句子属于什么从句?
1.You can sit where you like.
2.How it happend is a mystery to me.
3.That is why I object to the plan.
4.I have got the news that he will come back home.
5.Do you like the gift that I gave you as a birthday present.
6.I wonder if you could stay for another day.
最好简单的说下为什么.