He walked as a ghost walks, without displacing the air of the room, without shaking the objects which he touched.

他像鬼魂一样走路， 没有改变房间的空气， 也没有摇晃他所触及的物体。

The idea can be summarized point this: if a butterfly flaps its wings in one location, that could displace enough air to cause a tornado or some other large scale atmospheric storm elsewhere.

如果一只蝴蝶在某地扇动翅膀，搅动了足够的空气后可能导致别处发生龙卷风或其它大规模大气风暴。