I think you must do their homework every day

问题描述:

I think you must do their homework every day
这句话为什么有两个谓语think和do?

I think(主句)that you must do your homework every day.(从句,以that 为引导词,that 可省略)除了宾语从句的that可以省略,还有哪些从句的that可以省略?语法规则上只是宾语从句的引导词that可省略。