第6题: [单项选择]{{B}}Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. Hold her breath. B. Not to be annoyed. C. Not saying anything. D. Make further suggestions. 参考答案:C 答案解析:[听力原文]
W:I should tell them they shouldn’t waste money on such meaningless matter.
M:They never li
第30题: [单项选择]暗适应产生的原因是( ) A. 视杆细胞的视紫红质被分解 B. 视杆细胞的视紫红质合成增多 C. 视锥细胞的视紫红质被分解 D. 视锥细胞的视紫红质合成增多 参考答案:B 答案解析:[解析] 关于暗适应机制的解释,主要是化学反应说。克劳福德(Crawford,1947)确定视杆细胞中的视紫红质的化学反应过程是暗适应过程的机制。视紫红质(visual purple)是一种化学感光物