口A 回B 100 1000 800 400 0 33 0 20 40 60 80 1 2 3 A_____________ 1 ________________ 2 __________________ 3 ____________________ 0 50 100 150 200 1 2 3 B_____________ 1 ________________ 2 __________________ 3 ____________________ 0 200 400 600 800 1000 1200 1 2 3 C______________ 1 ________________ 2 __________________ 3 ____________________