It做形式主语时在什么情况下接doing?

it用作形式主语代替动名词的用法主要见于以下句式：
1. It is no use (no good, fun, great fun, a new experience, a great honour, etc) doing sth。如：
It is no good talking. 空谈是没有用的。
It’s fun working for him. 为他工作芦举很有意思。
It’s great fun sailing a boat. 扬帆驾舟十分有趣。
It’s no use shouting at him—纤颤he’s deaf. 向他叫喊是没有用的——他耳聋。
It has been a great honour your coming to visit us. 你来看望我们是极大荣幸。
2. It is good (nice, useless, interesting, pleasant, tiring, etc) doing sth。如：
It is useless speaking. 光说没有用。
It was pleasant sitting there. 坐在那里很愉快。
It’s so nice sitting here with you. 和你坐在一起真是愉快。
It’s good hearing English spoken. 听到人讲英语，我很高兴。
It’s terribly tiring working late like this. 这样干到深夜是非常累人的。
3. it is worth while doing sth。如：
It’s worth while doing the work. 这项工作值得做。
Do you think it’s worth while quarrelling with me? 你认为和我吵值得吗?
4. 其他句式。如：
It doesn’t matter wasting a little money. 浪陪竖碧费一点钱没有关系。
It felt funny being dressed like a peasant girl. 打扮成村姑感到有点怪怪的。
What’s it like being married? 结婚是什么味道。