为你解答.
We don't know when we shall give a fashion show (同义句）
We don't know (when) (to) (give) (a) (fashion) (show).
I have something to tell you. it's important enough.(合并句子）
i have (something) (important) (enough) to tell you.
这条围巾是由什么制成的?
(What's) this (scarf) (made) (of)?
这件套头衫是羊毛制的吗?
(Is) this (sweater) (made) (of) (wool)?
你应该再花点时间学习.
You should (spend) (more) (time) in studying.
I would like to live in a house (C among) many green trees.
解释：among意思是“在（三者以上）之中”.