Question

I happened to be out when he dropped in这句中,in 后面可以不加宾语吗?介词后面

Answer 1

这里是介词后置,不可以用一般的语法去定性介词后一定要加介词,在很多时候会遇到介词后置的情况,如：①He has a pen to write with.② He is the man whom we should wait for.③ I know the man that Tom is talking

至于到底哪几种情况要介词后置,你可以去其他地方查,因为涉及到的知识点很多,我这样解释你听不懂