1 . 稀薄
...efaction(同义:提纯→纯化/ 使稀薄→稀薄)反义词:condensatio n(浓缩)(记) rarefy(使稀薄)+ac tion
2 . 使稀薄
rare adj. 稀有的 scarce, uncommon, infrequentrarefyvt. 使稀少,使稀薄rarely adv. 很少地,罕有地 seldom, hardly ever.
3 . 抽空
rarefaction 稀薄[化]rarefy稀释;使稀薄,抽空rare metal 稀有金属
4 . 使稀少
rare adj. 稀有的 scarce, uncommon, infrequentrarefyvt. 使稀少,使稀薄rarely adv. 很少地,罕有地 seldom, hardly ever.