It's your duty__the classroom___.A to keep ,clean B to keep ,cleaningC keep,clean D for keeping ,clean

问题描述:

It's your duty__the classroom___.A to keep ,clean B to keep ,cleaning
C keep,clean D for keeping ,clean

A

选A
it is one`s duty to do s.th做某事是某人的职责
形容词clean在这里做宾语classroom的补语

A 保持教室干净整洁是你的义务. 此处是It 做形式主语的用法 It is .+to不定式 同时keep+sth+adj.形式中宾语补足语应该为形容词adj.形式