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.
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。
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Separately, Toyota said Monday it has expanded a U.S. service campaign for leaking oil hoses to cover 934,000 vehicles with six-cylinder engines.