a. 难以置信的

believe/unbelievable/belief/trust/faith/doubt/doubtful/suspect/skeptical
记忆：
1. believe vt. 相信 I believe that you can believe in yourself. 我相信你会有自信的。 believe sb相信某人的话 believe in sb信任某人 believe sb to be相信某人是 believe that
2. 加否定前缀un-和形容词后缀-able： unbelievable adj. 难以相信的 The news he brought us was unbelievable. 他带给我们的消息难以置信。
3. belief [ n. 信念，信仰 People live with some kind of belief. 人活着，就有某种信念。
4. trust n.& v. 信任，信赖 Thank you for your trust. I will do my best not to disappoint you. 谢谢你的信任。我会尽力不让你失望的。 格言：Where there is no trust there is no love. 爱要信任。
5. faith Confident belief in the truth, value, or trustworthiness of a person, an idea, or a thing n.信任, 信念, 宗教信仰, 忠实 I have faith in him! 我相信他！ 格言： Faith will move mountains. 精诚所至，金石为开。
6. 加形容词后缀-ful: faithful adj.守信的, 忠实的, 详确的, 可靠的 He is a faithful friend. 他是个值得信赖的朋友。
7. doubt [ daut ] 联想double, 二，不是唯一的，不能确凿的，n. & v. 怀疑 I doubt whether he is fit for the job. 我怀疑他是否适合这工作。
8. 加形容词后缀-ful: doubtful adj. 怀疑的 He looked at me with a doubtful eye. 他用怀疑的眼光看着我。
9. suspect To have doubts about; distrust vt. 怀疑 n.嫌疑犯 I suspect his motives. 我怀疑他的动机。
10. skeptical Marked by or given to doubt adj. 怀疑性的,好怀疑的 I am skeptical of his explanation. 我不相信他的解释。
另类阅读：
Some people have a faith in Chen Shuipian’s unbelievable belief, but more people are doubtful about it. The international world also suspects his plan.