二冲程发动机使用更多的汽油，燃烧更多的燃料，所以产生更多的污染。

However, a two-stroke engine USES more gasoline and burns lots of oil, so it is far more polluting.

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在二冲程发动机中你必须混和燃料和气体，因为气缸壁上的孔阻止使用活塞环密封燃烧室。

You have to mix oil into the gas in a two-stroke engine because the holes in the cylinder wall prevent the use of rings to seal the combustion chamber.

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随着活塞现在位于下止点且所有气体已经燃烧，重要的是要在工作循环的第四个即最后一个冲程中将所有的已燃废气从气缸中排出。

With the piston now at BDC and all the gases having been burnt, it is important to remove all the burnt gases from the cylinder on the fourth and final stroke of the cycle of operations.

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