穿过芯片的电子可以“识别”某一磁场，该磁场每隔几百纳米(十亿分之一米)就变换一次方向。

Electrons flowing through the chip would "see" a magnetic field that flips from one direction to the opposite every few hundred nanometres (billionths of a metre).

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舌头可以变换几次方向。

You can move your tongue in various directions.

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在一个平面上，做90度旋转的变换，逆时针方向。

Let's say that in the plane we look at the transformation that does rotation by 90 degrees let's say, counterclockwise.

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