think的过去式和过去分词是什么

　　例句：

　　1、I certainly think there should be a ban on tobacco advertising.

　　我确实认为应该禁止香烟广告。

　　2、Nora thought he was seventeen years old.

　　诺拉觉得他有17岁。

　　3、You were probably brought up to think like that.

　　你可能从小就被教育那样考虑问题。