可以,只要有动词、介词等,后面就可以跟名词,如果跟句子,就是宾语从句了.
如：talk about what happened yeaterday.：谈论昨天发生的事故.about 后就是宾语从句.
to do what you should do.做你该做的事情.what you should do就是 to do 后的宾语从句.
study what you should study ：学你该学的知识.what you should study 就是及物动词study 后的宾语从句.
To find who did this is important 中To find who did this 是主语,is important 是谓语和表语.who did this只是find的宾语而已,不是全句的宾语.