It is our duty ( )our hometown clean and beautiful.We must d

It is our duty ( )our hometown clean and beautiful.We must d It is our duty _________our hometown clean and beautiful. We It is our duty to keep our classroom clean and tidy.中的It《our It is our duty to keep our classroom clean and tidy.中 our du It is our duty to keep our classroom clean and tidy.句中的 clea It is our duty to keep our schoolyard clean and tidy.这句话是主语从 It is our duty to keep our e___ clean and tidy Our hometown is getting more beautiful and more beautiful. It is our duty to keep our classroom clean and tidy.这句话谁做主语谁 We feel _____ our duty to keep our city clean and tidy. I think it's our duty to keep our environment clean and tidy We must keep our classroom clean and tidy句子结构