drop in on和drop in at的区别：含义不同、用法不同、强调重点不同。drop in on中文含义为“拜访某人”，多指在计划之外或事先未打招呼偶然的拜访；drop in at中文含义为“拜访某地”，可指顺便访问，也可指参观。
一、drop in on的含义及用法
drop in on意为拜访某人。例句有：
1、I thought I'd drop in on you while I was passing.
我曾想路过时顺便来看看你。
2、My neighbor would drop in on me from time to time.
邻居们时不时到我家串串门。
3、She might drop in on us if she came here tomorrow.
假如明天来这里，她可能会顺便来看我们。
4、Next time you are in Guangzhou, please drop in on me.
下次来广州请一定来看我。
5、Will you drop in on us tomorrow evening for a talk?
你明晚顺便来和我们一起谈谈好吗？
6、When I drop in on him yesterday he was not at home.
我昨天顺路去看他，但他不在家。
7、The address, he decided to drop in on the old scientist.
知道了地址，他决定拜访这位老科学家。
二、drop in at的含义及用法
drop in at意为拜访某地。例句有：
1、I usually drop in at his place on my way home.
我回家时，通常顺便到他那里看看。
2、Don't you sometimes drop in at her house?
你不是有时候会顺便到她家去吗？
3、Please drop in at my office when you happen to be free.
如果你碰巧有空的话，请到我的办公室来。
4、Shall we drop in at a coffee shop?
我们顺便去一下咖啡店好吗？
5、Connie's For ladies and gentlemen Drop in at any time!
康妮发廊为各位男士女士们服务欢迎随时光临！
