请问drop in on 与drop by有什么区别

问题描述:

请问drop in on 与drop by有什么区别

drop in on后接表示人的名词或代词,而drop in at后接表示处所的名词或代词.如:
I thought I'd drop in on you while I was passing.我曾想路过时就来看看你.(指人)
(指处所)