第27题: [单项选择]吞噬杀伤活性最强的细胞是(). A. NK细胞 B. T细胞 C. B细胞 D. 中性粒细胞 E. 嗜碱性粒细胞 参考答案:D 答案解析:1.B细胞能分化为浆细胞并分泌抗体。2.NK细胞表面具有CD56分子,具有非特异性杀伤肿瘤细胞的作用。3.肥大细胞和嗜碱性粒细胞表面高表达高亲和力IgE受体。4.与单核巨噬细胞比较,中性粒细胞吞噬杀伤
第36题: [单项选择]— Did you come to the museum by bike yesterday —No. Two metres of snow fell during the night. As a result, several main roads ______. A. were blocked B. had been blocked C. were being blocked D. have been blocked 参考答案:A 答案解析:[解题指要] 该题测试动词时态以及语态的用法。题中Did you come…中的Did是关键词。 As a result 指当时的“结果是……”,故选用一般过去时配合。B选项had been bloc