When the engine is shut off, the intake manifold cools and a slight vacuum forms as a result .

这是因为当发动机熄火时，进气歧管冷却而产生轻微的真空。

youdao

When the engine is shut off, the intake manifold cools and a slight vacuum forms as a result .

这是因为当发动机熄火时，进气歧管冷却而产生轻微的真空。

youdao