You cannot clap with one hand. 

孤掌难鸣

(ɡū zhǎnɡ nán mínɡ)

A: Did you hear about that? Wang Xiang's company is brankrupt.

A: 你听说了吗？王翔的公司倒闭了。

(nǐ tīnɡ shuō le ma? wánɡ xiánɡ de ɡōnɡsī dǎobì le.)

B: Really? It's the first time I heard about it.

B:是吗？我第一次听说。

(shì ma? wǒ dìyīcì tīnɡshuō.)

A: Only Wang Xiang himself was working hard for that company. You know, you cannot clap with one hand.

A: 那家公司就王翔一个人在努力,孤掌难鸣啊。

(nà jiā ɡōnɡsī jiù wánɡ xiánɡ yīɡèrén zài nǔlì, ɡū zhǎnɡ nán mínɡ ā.)