step为什么要双写

因为它是重读闭音节。She moved a step closer to me.

她朝我靠近一步。

There was a bounce to his step.

他的步伐矫健有力。

He took a step towards the door.

他朝门口迈了一步。

I took a step toward him.

我朝他迈出了一步。

He took a step backwards.

他退后一步。