Forepump
前置真空泵, 预抽真空泵
🗣️ 情景例句
It's about the size of the United States, but it has a population of only 16.5 million.
它和美国一般大，但人口却只有一千六百五十万。
I am afraid you don't see my point.
恐怕你没有明白我的意思。
Because of his revolutionary views, he spent many years in prison.
由于他的革命观点，他在监狱里度过了许多年。