forget doing sth与 forget to do sth 用法的区别

问题描述:

forget doing sth与 forget to do sth 用法的区别

forget to do sth是忘了干某事(还没干呢);forget doing sth 是忘了干过的某事(干过,但是忘了).
比方说,
I just forgot to fetch the file. 我忘了拿那份文件.(真的没有拿)
I just forgot fetching the file. 我忘了已经拿了那份文件了.(拿了,但是忘了曾经干过这件事)