首先,没有谓语从句!
主语从句作为主语,放在主语的位置上!e.g.
What I want to know is your grammar.
Whether she'll come is uncertain.
When they will go to Beijing is not decided.
How much they will pay is unknown.
宾语从句作为宾语,放在宾语的位置上!e.g.
They don't care what I want to know.
I don't know whether she'll come.
They can't decide when they will go to Beijing.
Do you know how much they will pay?