11. Are you serious? 你是认真的吗?
12. I doubt it. 我怀疑。
13. I am doubtful about that 我对此表示怀疑。
14. Don't expect me to believe this. 别指望我相信这事。
15. It can't be true. 不可能是真的。
16. How is that possible? 那怎么可能呢?
17. He is a doubting Thomas. 他是个疑心很重的人。
18. I never take him too seriously. 我从来不把他的话当真。
19. I feel puzzled. 我感到很茫然。
20. It's doubtful whether this will work. 我怀疑这会不会起作用
