Today I would like to introduce you to a very common saying that is used by Chinese locals everyday. 不会吧? Bú huì ba?, translated roughly means: “No way!”, or “You’re kidding me?”. This is used to express disbelief at what the other person(s) said or did. Below are contexts in which the phrase is used, with some examples following:
1. If something very good, bad, and/or unexpected has happened, this expression can be used to simultaneously show excitement and/or disbelief.
2. Sometimes this will be used to express that what has been said by another party is next to impossible.
1. A: 今天下午咱们的邻居被警察带走了，好像他跟一起杀人案有关系。
(Zuótiān xiàwǔ zánmen de línjū bèi jǐngchá dài zǒu le, hǎoxiàng tā gēn yìqǐ shā rén àn yǒu guānxì)
Translation: Yesterday afternoon our neighbor was taken away by the police, it seems that he is has some relationship to a murderer.
B: 不会吧？ 他是那么老实一个人。
(Bú huì ba? Tā shì name lǎoshi yígè rén.)
Translation: No way! He is such a good and honest person.
2. A: 他说昨天是因为拉肚子才没来上课的。
（Tā shuō zuótiān shì yīnwèi lādùzi cái méi lái shàngkè de.）
Translation: He said that yesterday he did not come to class because he had diarrhea.
(Bú huì ba? Zuótiān wǎnshàng wǒ hái zài kǎoròu diàn kànjiàn tā le ne.)
Translation: You’re kidding me? Last night I saw him at a barbeque meat restaurant.
刘德联， 刘晓雨。 汉语口语常用句式例解 Exemplification of Common Sentence Patterns in Spoken Chinese
Beijing: Peking University Press, 2005.