A supercharger rams additional air into the cylinders.

用增压器向气缸内推送额外的空气。

US officials have warned Tehran against any escalation and Washington is sending additional air defense systems to the region.

美国官员警告德黑兰不要造成任何局势升级，华盛顿正在向该地区派遣更多的防空系统。

In a statement Press Secretary John Kirby said the two additional air strikes were carried out to defend the city of Erbil where US personnel are based.

在一份声明中，白宫新闻发言人科比(John Kirby)表示，为了保卫美国工作人员所在城市伊尔比尔，美国再次发动了两起空袭。