I think后面一般不加动词，而是要加从句。而且从句只能用肯定式，如果表达否定的意义，则把not放在主句中，这叫做否定转移。
1) 将think, believe, suppose, expect, fancy, imagine等动词后面宾语从句的否定词转移到主句中，即主句的谓语动词用否定式，而从句的谓语动词用肯定式。
I don't think I know you. 我想我并不认识你。
I don' t believe he will come. 我相信他不回来。
注意：若谓语动词为hope,宾语从句中的否定词不能转移。
I hope you weren't ill. 我想你没有生病吧。
2) 将seem, appear 等后的从句的否定转移到前面。
It doesn't seem that they know where to go.
看来他们不知道往哪去。
It doesn't appear that we'll have a sunny day tomorrow.
看来我们明天不会碰上好天气。
