请从语法角度加以说明~（4）
问题描述：
请从语法角度加以说明~（4）
44.breathing equipment ____ protecting firemen from smoke.
A.used to B.is used for C.is used to D.use to
46.my father prefers to stay at home rather than _________ on may day.
A.travel D.travels
答
44.used to do sth.意思是习惯于,惯于做某事；be used to do sth.被用来做什么；be used for doing sth.被用来做什么.本题的意思是呼吸用具是用来保护消防员免受烟雾的侵害.题目中的动词是动名词形式,根据上面句型选...