问题 这里的it指代的是什么

When I visited the spot a few days ago, it was to discover that bounty-hunters had been the night before.这里粗体的“it”指代的时候是“情况”“状况”等？还是作形式主语或者指代spot，而后面的to discover不定式为主动表被动？希望老师解惑，谢谢...

问题 works用什么代词来指代（it还是them)

Some complain that literary works are so thick that they hardly have  enough patience to finish it.其中 it 为什么不改为 them？前面的 works 不是复数吗？

问题 It is...since...的主句与从句时态

It was three years since Jack had been a teacher.It is three years since Jack was a teacher.请问这两句有什么区别吗？分别是什么意思？第二句为什么不用has been呢？

问题 如何理解：What business is it of yours?

What business is it of yours? 请问这个句子是什么意思？特别是句中的 is it of 如何理解？

问题 as 的用法（指代主句整句内容与部分内容）

...that?FEMALE PROFESSOR: Yes, the octopus can release a cloud of ink if it feels threatened, ah but it doesn’t hide behind it, as is generally believed.FEMALE PROFESSOR: Um the ink cloud is... it serves to distract a predator while the octopus makes its escape.请问老师，这里的as是...

问题 for sb与to sb (it looks gloomy to me)比较

—It’s a nice day, isn’t it?—Yes, but it looks gloomy to me.句子中的 to 可以换成 for 吗？

问题 Really? Can’t it wait until tomorrow ?

Really? Can’t it wait until tomorrow ? 这句话为何是can't 放在句首呢？不是应该放在it 后面么？

问题 分析: There could be no doubt about it.

There could be no doubt about it. 请问介词短语about it做什么成分？

话题 It和that

话题 it的指代问题

话题 it作形式宾语

话题 it代词指代啊

话题 It和one

话题 it is用法

话题 形式主语it用法