Adverb 万一 (Just in Case / If by Any Chance)

Pattern

• 万一 + Condition，Subject + 就 + Verb
• 万一 + Condition + 怎么办

Usage

• 万一 (wànyī) means “just in case”, “if by any chance”, or “in the unlikely event that”.
• It presents a hypothetical scenario that has a very low probability of happening, but would have significant negative consequences if it did — hence necessitating prior preparation.
• Difference from 如果 (if): 如果 is a neutral conditional conjunction (e.g., 如果你来, 我们一起吃饭 - If you come, we'll eat together).
• In contrast, 万一 carries an inherent tone of worry, alert, or contingency planning: 万一下雨怎么办?
• (What if it rains?).

Examples

1. 1

   你最好带把伞，万一下雨呢？

   Nǐ zuìhǎo dài bǎ sǎn, wànyī xià yǔ ne?

   You had better take an umbrella, what if it rains?

2. 2

   万一你不能来，请提前告诉我。

   Wànyī nǐ bù néng lái, qǐng tíqián gàosu wǒ.

   In case you cannot come, please let me know in advance.

3. 3

   我们多准备一些，以防万一。

   Wǒmen duō zhǔnbèi yīxiē, yǐ fáng wànyī.

   Let us prepare a bit more, just in case.