要不（然）

快走吧，要不然就来不及了。

Kuài zǒu ba, yàobùrán jiù láibùjí le.

Hurry, or we won't make it in time.

你先吃饭吧，要不然菜就凉了。

Nǐ xiān chīfàn ba, yàobùrán cài jiù liáng le.

Eat first, or the food will get cold.

我们打车去吧，要不太晚了。

Wǒmen dǎchē qù ba, yàobù tài wǎn le.

Let's take a taxi, or it'll be too late.