Word: 不行

他买一把刀行，我买就不行了吗？

Tā mǎi yì bǎ dāo xíng, wǒ mǎi jiù bùxíngle ma?

If it's okay for him to buy a knife, then why on earth can't I?

他要不行了。

Tā yào bùxíngle.

He's on his last legs.

企者不立，跨者不行。

Qǐzhě bú lì, kuàzhě bùxíng.

The one who tip-toes does not stand; the one who strides widely does not walk.

体育我很不行。

Tǐyù wǒ hěn bùxíng.

I am not good at sports.

我想还待一夜，行不行？

Wǒ xiǎng hái dài yí yè, xíng bùxíng?

I'd like to stay one more night. Is that possible?

我觉得这主意不行。

Wǒ juéde zhè zhǔyi bùxíng.

I don't think this is a good idea.