If you spin a top, that we know that the top will not last very long because of friction.

如果你转一个陀螺，你会发现因为摩擦力，陀螺不会永远旋转。

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The efficiency of a real system is always less than 1 because of friction between moving parts.

由于运动部件之间存在摩擦力，所以实际系统的效率永远小于1。

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Between each pocket there is a metal stick to make frame firm and strengthened, and avoid the breaking because of friction under the high air velocity.

每个滤袋间一金属条固定，增加强度，并防止滤袋于高风速时，因风切之摩擦力而破裂。

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This works because gravity holds you firmly on the ground, and your feet stay put because of friction with the floor.

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But while this works in Latvia, a relatively marketised economy, in Greece there is a lot of friction - and not just because of organised labour resistance.

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But if one person's mind was changed because of her actions, Foster said it was worth the nerves and friction.

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