As the piston travels upward, it pushes the spent gases out through the open exhaust valve.

活塞的上行通过排气门将废气排出汽缸外。

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Modern car engines that use rolling or sliding tappets for transmitting the rapid up-down lifting motion of the spinning camshafts—to open and close the engine’s inlet and exhaust valves—seem immune.

使用滚柱挺杆或滑动挺杆来传动旋转凸轮轴做上下快速提升动作（开启和关闭发动机的进气阀和排气阀）的现代型汽车发动机似乎不会出现上述自动熄火的情况。

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If the valves do not open and close at the right time or at all, air cannot get in and exhaust cannot get out, so the engine cannot run.

如阀门打开或关闭的时间不对或根本打不开或关不住，空气无法进入，废气无法排出，因此发动机不运转。

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But he has left open the possibility that he will wait until next year, thereby allowing his opponents to exhaust their momentum and their thin resources.

ECONOMIST: The prime minister keeps the opposition waiting