we look forward to your coming.

i'm looking forward to your coming.

为什么两句话一句用look，一句用looking呢？？什么意义有什么不同呢？？？

1、从语气上来说，-ing 形式比较personal 和friendly，和 look forward to...相比较少为正式，如果你要表示礼貌而有亲和力则用looking forward to...，look forward to在非常正式严谨的business场合比较适用。

2、国外英语论坛上native speaker给的解释二：

“The difference is how the speaker perceives their own words:

an action seen as a whole/accomplished (I look forward...) or continuing (I am looking...).

一个动作的结束（look forward to...）和一个动作的持续（looking forward to...）

look forward to   and  looking forward to。持续与已结束。