其中的每一种动物代表一个阴历年份它们，顺序固定，而且这一循环每 12 年 往复一次。

Each of them represents a lunar year. They appear in a fixed order and the cycle repeats every 12 years.

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四冲程循环发动机中，四个冲程的固定顺序是：进气、压缩、作功和排气。

The four strokes in the four-stroke-cycle engine, in their proper order, are intake, compression, power, and exhaust.

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