矿井瓦斯，有毒气体矿井中有时污染空气的恶臭气体或有毒气体 Foul or poisonous gas that sometimes pollutes the air in coal mines.
经过特别警告巴格达不得在伊拉克任何地方使用毒气和作战飞机（这些警告鼓励了少数民族叛变）以后，当伊拉克继续用作战直升机对付叛军时，布什却半途而废未加制止。 After having pointedly warned Baghdad not to use poison gas or combat aircraft anywhere in Iraq, warnings that had encouraged the rebellion, Mr.Bush pulled up short when Iraq continued to fly combat helicopters against the insurgents.
