请看下面的句子:Who is knocking at the door?I think (it) is Li Lei.为什么要用it?

问题描述:

请看下面的句子:Who is knocking at the door?I think (it) is Li Lei.为什么要用it?

敲门这个动作中的who跟后文的it相同,it代指who,我认为,敲门的话这个动作可以是动物,可以是别的东西,未必是人,所以未必用he/she.用it就包含所有可能了....

代指 Who is knocking at the door?中的 who.