The new ventilation system expels stale air from the conference room every ten minutes.

新的通風系統每十分鐘就會把會議室裡的污濁空氣排出去。

Our factory upgrade cut the amount of waste gas expelled into the air by half.

我們工廠升級後，排放到空氣中的廢氣量減少了一半。

The cargo ship's engine expels less smoke after the maintenance crew replaced the filters.

維修人員更換濾網後，那艘貨輪的引擎排出的黑煙變少了。