2 sentences

1. 建筑工人在高空进行作业时必须戴安全帽。

   jiàn​zhù​gōng​rén zài gāo​kōng jìn​xíng zuò​yè shí bì​xū dài ān​quán​mào.

   Construction workers must wear safety helmets when working at heights.

   Source: Dong Chinese Dictionary

2. 建筑工人们在今天早晨铺设了这栋大楼的基石。

   jiàn​zhù​gōng​rén men zài jīn​tiān zǎo​chén pū​shè le zhè dòng dà​lóu de jī​shí.

   The construction workers laid the cornerstone of this building this morning.

   Source: Dong Chinese Dictionary