Gōng / zuò / rén / yuán / zhèng / zài / jiǎn / chá / dà / lóu / de / fáng / huǒ / tī / shì / fǒu / chàng / tōng.

工作人员正在检查大楼的防火梯是否畅通。

The staff are checking whether the building's fire escape is clear.