Then, an intake valve opens, allowing the steam into the engine.

然后，进气阀打开，让 蒸汽进入发动机。

Then, an intake valve opens, allowing the steam into the engine. The steam expands and moves a piston outward – that’s the work done by the engine.

然后，进气阀打开，让蒸汽进入发动机。蒸汽膨胀并向外移动活塞——这就是发动机所做的功。