多项选择题答案(共30题，每题2分。每题的备选项中，有2个或2个以上符合题意，至少有1个错项。错选，本题不得分;少选，所选的每个选项得0.5分)
51.BCDE 52.CE 53.BCE 54.ACD 55.ABCD 56.BDE 57.ACDE 58.BD 59.ABCE 60.CDE 61.BCE 62.ACD 63.ABC 64.ACD 65.AE 66.ABD 67.BCE 68. ADE 69.BCE 70.BCDE 71.ABE 72. ACD 73.AB 74.AD 5.ABE 76. ADE 77.BC 78.BCDE 79.CD 80. AC