大家好,麻烦帮我翻译下这几个英文句子?

1 He has been back and he left a note for you .
他已经回来了还给你留了个条子呢。

2 Should he come ,what would you say to him?
他如果回来的话，你将如何对他说呀？

3 Tell me since when he has taught in your school.
请告诉我他是从何时开始在你学校任教的。

4 When we visiting the museum is not decided.
我们什么时候去博物馆还没决定呢

6 The only thing the master could to return to the mountain hut where they had spent the night.
唯一一件事就是主人（是否）能回到他们曾度过那个晚上的那个山上的小屋中。

1 He has been back and he left a note for you.
他已经回来了并且留了张便条给你。
2 Should he come, what would you say to him?
如果他来了，你会对他说些什么？
3 Tell me since when he has taught in your school.
告诉我他从什么时候开始就在你们学校教书了。
4 When we (可能缺are)visiting the museum is not decided.
我们什么时候参观博物馆还没决定。
6 The only thing the master could (可能缺do was) to return to the mountain hut where they had spent the night.
那主人（硕士）唯一可做的事就是回到那个我们度过一夜的山间小屋。

1 He has been back and he left a note for you