look forward to 后面永远跟动词ing形式吗?即使前面有个have been 后面的动词不用变过去式的吧?

问题描述:

look forward to 后面永远跟动词ing形式吗?即使前面有个have been 后面的动词不用变过去式的吧?
比如说i have been looking forward to ----from my parents.

这道题应该接动词的ing形式,hearing.
不过不能说look forward to 后一定接动词的ing形式,要考虑句子成分以及句子的意思.如:
The letter he has been looking forward to arrived yesterday. 在这个句子中he has been lookingforwardto 充当的是定语成分,后面arrived是句子的谓语.即The letter arrived yesterday.
He looked forward to see what was happening 这句话的意思是:他向前看,目的是看一下发生了什么事.to see 是目的状语.