第2题: [单项选择]B因子溶血活性测定中,在缓冲液中加入EGTA是为了螯合反应体系中的() A. Mg2+ B. Ca2+ C. Zn2+ D. Fe3+ E. P3+ 参考答案:B 答案解析:B因子是旁路途径的补体因子,经典途径需有Ca2+及Mg2+参与,旁路途径只需Mg2+的参与,用EGTA的目的是螯合钙离子,抑制经典途径
第18题: [单项选择]Questions 19 to 22 are based on the conversation you have just heard.[A] It suits him. [C] It looks old. [B] It looks ridiculous. [D] It’s getting worse. 参考答案:A 答案解析:[听力原文] What does the woman think of her husband’s baldness