参考答案:
1---5. BAABB 6---10. AABAA 11---15. ABABB 16---20. DBBDB
21---25. DBBAB 26---30. DAADC 31---35. BCDDB 36---40. BBBDD
41---45. CBDBC 46---50. CABAA
51---55. DDBCD 56---60. BAAAD61---65. ABCBB 66---70. BCDBA 71---75. CDCDD 76---80. CABCA81---85. ABCDA 86---90. ABCDA 91---95. BCDAB 96---100. CDDCD