Question

think后加动词的什么形式

Answer 1

think后面一般都跟从句，或者后面跟of或者about；但也有加不定式的情况，think to do sth 设法做某事，例如：They had thought to deceive me，他们想骗我。但是think后面跟其他形式的动词我倒还真没见过

Answer 2

加 to do sth
还有加that 宾语从句

Answer 3

think + to do sth. 但这种用法很少见的。要注意词义：
1、= to expect to do sth.
e.g. I didn't think to meet you here. = I didn't expect to meet you here. 没有料到
2. = to remember or to plan to do sth.
e.g. I didn't think to tell you about it beforehand. 没有想到，没有考虑到