3 sentences for 万一 (wàn​yī — contingency)

1. 万一迷路，就打电话给我。

   wàn​yī mí​lù, jiù dǎ diàn​huà gěi wǒ.

   Call me if you get lost.

   Source: Dong Chinese Dictionary

2. 我们要做好准备，以防万一发生不测。

   wǒ​men yào zuò hǎo zhǔn​bèi, yǐ​fáng wàn​yī fā​shēng bù​cè.

   We must be well-prepared in case of any unforeseen circumstances.

   Source: Dong Chinese Dictionary

3. 他万一有个好歹，我怎么向他家人交代？

   tā wàn​yī yǒu gè hǎo​dǎi, wǒ zěn​me xiàng tā jiā​rén jiāo​dài?

   If anything happens to him, how can I face his family?

   Source: Dong Chinese Dictionary