不安全

zhè xiē jiàn zhù yǐ hěn chén jiù yǒu xiē hái bù ān quán

这些建筑已很陈旧，有些还不安全。

The buildings are ageing, and some are unsafe.

gōng shuǐ bù ān quán

供水不安全。

The water supply is unsafe.