根据上下文，补全对话。(12分)
A: Look              our classroom.    
B: Oh, it  is  very dirty.
A: Let’s keep our classroom              .
B: All right. I can              the rubbish              the bin.
C: I can              the floor with Lily.
D: I can              the desks and chairs.
A: Good idea. Let’s start.                
B&C&D: OK!