It would clear the air. 
The air would be cleared by it.
It lacked the capacity to clear the air.
The motorcycle is moving.
The prefect of Paris kept all of the medieval structures.
The men are playing a game.
A woman with a receded hairline is in a chemistry lab working with several beakers.
A cable car carries you up over 6000 feet onto Mont d'Arbois offering a magnificent view of the Aravis peaks and Mont Blanc.
A boy are playing with some other childrens