单词	保护圈
释义	同保护圈--保护环
随便看	double headed rail double-headed rail double headed spike double header double-header doubleheader double-header boiler double heading double heading cock double headings double head latch needle double head milling machine double head rail double head receiver double headreceiver double head spanner double head (telephone) receiver double head [telephone] receiver double head(telephone) receiver double head type double head wrench double head wrench (double head spanner) double heart curve double hearted double-hearted