5 sentences

1. 难道你还没听懂不成？

   nán​dào nǐ hái méi tīng​dǒng bù​chéng?

   Is it possible that you still don't understand?

   Source: Dong Chinese Dictionary

2. 这件事我看是办不成了。

   zhè jiàn shì wǒ kàn shì bàn bù​chéng le.

   I don't think this can be done.

   Source: Dong Chinese Dictionary

3. 礼物菲薄，不成敬意。

   lǐ​wù fěi​bó, bù​chéng jìng​yì.

   This humble gift is but a small token of my respect.

   Source: Dong Chinese Dictionary

4. 你疯了不成？

   nǐ fēng le bù​chéng?

   Are you nuts?

   Source: OpenSubtitles

5. 如果他不答应，那可不成。

   rú​guǒ tā bù dā​ying, nà kě bù​chéng.

   If he doesn't agree, that simply won't do.

   Source: Dong Chinese Dictionary