In the past, ice used to ______ used to ______ tbe air in a room.

A.be; cool

B.be; cooling

C.being; cool

D.being; cooling

答案及解析： A

本题同时考查use的本义用法及含有used的词组 。其正确句意应为：在过去，冰曾经被用来冷却屋子里的空气。将used to do sth.与be used to do sth.合二为一，则成了used to be used to do sth.。