题目内容：

The chemistry teacher required the students___more attention ___the lab clean.A.to pay,to keep
B.to paying,to keeping C.paying,keeping D.to pay,to keeping
求详解

优质解答

D required sb.to sth.要求某人做某事 pay attention to doing 注意某件事”,对某事加以关注 to为介词用doing doing 可省略

追问：

pay attention to doing 是固定词组还是什么

追答：

固定的，这俩都是固定的，要记住