Unit five It must belong to Carla.一、单项选择1. - Can you swim in the river?- No, I _.A. mustnt B. may not C. cant D. neednt 2. - ay I go swimming now? - No, you _. You must finish your homework first.A. mustnt B. may not C. couldnt D. neednt 3. - Excuse me. Where is the zoo? - Sorry, I dont know. Ask that policeman. He _ know.A. shall B. may C. need D. would 4. _ I finish