但当有人从上而下推按你的肩膀时情况就不同了，这时你不需要顶抗，就会毫不费力吸收掉作用在身体上的力。
But it will be different if someone pushes down on your shoulders. In this situation you do not push back up - you just absorb the push effortlessly into your posture.
从理论上讲，千斤顶的顶力可以任意进步，从而也能达到任意长度的推顶间隔。
Theoretically, the jacking force can be enhanced arbitrarily, so the jacking distance can reach arbitrary length.
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