Expressing "how about" with "yaobu"

要不 (yào bù) can have a number of meanings depending on how it is used.

要不 as 或者

• 你 要不 看书 要不 去 睡觉

要不 used for suggestions

要不 can be used as an indirect way of giving a suggestion, as the speaker is using 要不 to seek consent of the listener.

• 要不 我们 一起 去 吧。
• 要不 咱们 今晚 吃 湘菜。

要不 as 否则

要不 can also be used to mean otherwise:

• 你 快点 打电话 给 他，要不 他会 很 担心。
• 我 要 打的 要不 我会迟到。

要不然 can be used interchangably with 要不 when it is used as 否则.

Sources and further reading

Books

• Home With Kids1 (家有儿女1) (pp. 50)
• BRIDGE (桥梁 实用汉语中级教程下) (pp. 187)