请在用餐前洗手以防止细菌传播。

Qǐng zài yòngcān qián xǐshǒu yǐ fángzhǐ xìjùn chuánbò.

Please wash your hands before meals to prevent the spread of bacteria.

在火灾发生时，要迅速采取措施防止火势扩大。

Zài huǒzāi fāshēng shí, yào xùnsù cǎiqǔ cuòshī fángzhǐ huǒshì kuòdà.

In the event of a fire, take immediate measures to prevent the flames from spreading.

父母应该教育孩子如何防止受伤。

Fùmǔ yīnggāi jiàoyù háizi rúhé fángzhǐ shòushāng.

Parents should educate children on how to prevent injuries.