It's a long time since i saw you last 这句中的it是不是形式主语?
4个回答

记住:

It(形式主语) is / has been (系动词谓语) a long time(表语) since(主语从句连接词) i saw you last (後面全部是真正主语)

一样的道理:

I(主语) like (谓语)it (形式宾语)that / when / if (宾语从句的连接词)Spring is here with us (後面都是真正宾语).