他回来的消息传遍了整个村庄。(that 引导的同位语从句) The news that he came back have been spread all over the village. 你打败他是很难的。(that 引导的主语从句) That you defeat him is difficult.
回答(2):
When we wil start is the question. 我们什么时候出发是个问题。 I don't know where she comes from. 我不知道她是从哪来的。