何在

kùn nan hé zài

困难何在？

Wherein lies the difficulty?

tā jū xīn hé zài

他居心何在？

What is he up to?

wèn tí hé zài

问题何在？

Where in lies the problem?

yòng xīn hé zài

用心何在？

What's the motive?

tā jué de zì jǐ yǐ jīng zhī dào zhè cì tán huà de mù dì hé zài

她觉得自己已经知道这次谈话的目的何在。

She felt that she knew the purpose of the conversation.

wǒ bù zhī tā de mù dì hé zài

我不知她的目的何在。

I don't know what she is driving at.

nǐ děi ràng tā míng bai guān jiàn hé zài

你得让他明白关键何在。

You have to make him understand what the point is.