奈

wú nài

无奈

however

nài yuán jūn wèi zhì

奈援军未至。

But unfortunately the reinforcements didn't arrive.

nài hé

奈何

however

nài tā bù dé

奈他不得

can do nothing with him

wǒ shí zai shì nài bù zhù tā jiū chán bù xiū

我实在是奈不住她纠缠不休。

I really could not stand her constant bother.

nài zhī hé

奈之何

how to deal with him