look forward to后面什么时候跟to do,什么时候用doing?

look forward to 后面是一定要加doing的，要么加一个名词

你好
look forward:
期待
例句与用法:
1. We look forward to the return of spring.
我们期待着春天的到来。
2. I am familiar with his work and look forward to hearing his views on Literary and artistic creation.
我熟悉他的作品，并期待他能就文艺创作问题发表自己的见解。
3. I/We will be at the10 Baker Street at six sharp, and look forward to seeing you.
我（们）将于晚六点准时到达贝克大街10号，到时再会。
4. Come and bring your wife of other guest. We look forward to seeing you.
请您届时携带夫人或其他一位客人光临。我们期待着您的到来。
5. We should look forward to the futurity.
我们应该展望未来。
6. I look forward to being alone in the house.
我盼望著能自己一人在这所房子 .
英英解释:
动词look forward:
1. expect or hope for
好像没的跟doing呀
谢谢

给你两句句子
we are looking forward to holding a party.
我们很想开一个派对.
这里的to 是介词
He looked forward to see where his mother would go.
他向前看看了,想知道他妈妈要去哪里.
这里表示,往前看,to 是动词不定式
不懂问我

doing
在这里to是介词