7, 4, 14, 8, 21, 16, (), () A.20, 18 B.28, 32 C.20,32 D.28, 64 7, 4, 14, 8, 21, 16, (), ()A.20, 18 B.28, 32 C.20,32 D.28, 64 参考答案 查看答案