How far has the plane traveled, then, in horizontal direction?
飞机飞行了多远？，在水平方向？
The plane moves in one direction while the conveyer moves in the opposite direction.
翻译：飞机朝一个方向移动（所以，飞机并未固定），传送带朝反方向移动。
The plane was flying in a northerly direction.
那飞机在向北飞行中。
The plane was flying in a northerly direction.
那飞机在向北飞行中。
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