I think he is very old.

问题描述:

I think he is very old.
这个句子有错吗?句中,thank 是动词,is也是,中间怎么不接to或者后者+ing?

主句中谓语动词是think,而从句用that引导更好,that一般口语中省略.
I think (that)he is very old.