第13题: [单项选择]Questions 29 to 31 are based on the passage you have just heard. A. It’s one half as much as 1976. B. It’s twice as much as 1976. C. It’s close to the same. D. It’s two-thirds as much as 1976. 参考答案:A 答案解析:[听力原文] How much will the dollar buy in real goods now compared with 1976
第30题: [单项选择]抗M抗体最佳反应温度 A. 4℃ B. 22℃ C. 37℃ D. 56℃ 参考答案:A 答案解析:抗M抗体是较常见的天然抗体,在4℃反应最佳,37℃反应较弱或全部不反应。抗M在婴儿较多见。它主要属于IgM,但IgM和IgG同时存在者也不少见。抗N抗体较抗M少见。大多也为天然抗体,且为典型的IgM冷