Why does aperson standing in a bus or train tend to fall when a sudden start is made?
一个人站在公共汽车或火车上，当车突然开动时，他为什么会倾倒呢？
Why does a person standing in a bus or train tend to fall when a sudden start is made?
一个人站在公共汽车或火车上，当车突然开动时，他为什么会倾倒呢？
Why does a person standing in a bus or train tend to fall when a sudden start is made?
一个人站在公共汽车或火车上，当车突然开动时，他为什么会倾倒呢？
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