3 sentences

1. 我们还是带把伞吧，以防万一。

   wǒ​men hái​shi dài bǎ sǎn ba, yǐ​fáng​wàn​yī.

   Let's bring an umbrella just in case.

   Source: Dong Chinese Dictionary

2. 他还有我手机号码，以防万一。

   tā hái yǒu wǒ shǒu​jī hào​mǎ, yǐ​fáng​wàn​yī.

   He has my cell phone number, just in case.

   Source: OpenSubtitles

3. 我们得把她留在这里，以防万一。

   wǒ​men děi bǎ tā liú zài zhè​lǐ, yǐ​fáng​wàn​yī.

   We need to keep her here just in case.

   Source: OpenSubtitles