The classroom musta,clean b,be cleaned c,to clean d cleaning急,

The classroom musta,clean b,be cleaned c,to clean d cleaning急, the young trees mustA be well looked afterB be taken good care clean the classroom 保持-------the classroom clean. the backboard is()()()()the classroom he has cleaned the classroom 对 cleaned the classroom提问 learning outside the classroom 和 learning inside the classroom. Mark likes reading in the classroom.(in the classroom)提问 In the classroom,I sit___Tom Some students [ ] in the classroom let is clean the classroom? who ____(clean) the classroom? Wendys at the classroom door . i must____(clean) the classroom. come out of the classroom let's d____in the classroom What in the classroom?回答 what,s in the classroom?