it our duty ___[keep]our classroom clean every day【这个题该怎么答?这是关于it的什么公式?求关于上面那道题的it公式.

It is our duty to keep the classroom c--------. It's on duty to keep our classroom clean 改为同义句_______ ________ our classroom clean is our duty. Waste paper should be throun every were,It's our duty to keep our city clean I think it's our duty to keep our environment clean and tidy. It is our duty to keep our e___ clean and tidy Don't t_____ here and there.It's our duty to keep our school clean it our duty ___[keep]our classroom clean every day【这个题该怎么答?这是关于it的什么公式?求关于上面那道题的it公式. It is our duty to keep our school clean keep 后不是接动名词吗为什么是clean It is our duty to keep our classroom clean and tidy.中的It《our duty 》和 clean and tidy是什么成分 It's our duty to keep the balance of （n ）以n开头的词 It is our duty to keep our classroom clean and tidy.句中的 clean and tidy是什么成分?为什么? It is our duty to keep our classroom clean and tidy.这句话谁做主语谁做谓语 It is our duty to keep our city clean.中文该怎么翻译?它的同义句是什么? Don't throw waste paper everywhere.It's our duty to keep our school_____ A.clean B.cleaing I think __our duty to keep our evirionment clean an tidy.A.this B.that C .it D.it's our duty is ___(save ) water it is everyone's duty to___-our school a pleasant place to learn infind set keep make Our classroom?every dayA.cleans B .is cleaning C.Is cleanedSo it is.It's our duty to keep it clean and tidy