第31题: [单项选择]完成一个反射所需时间的长短主要取决于 A. 传入与传出纤维的传导速度 B. 刺激的强弱和性质 C. 突触的多少 D. 感受器的敏感性 E. 效应器的敏感性 参考答案:C 答案解析:突触延搁:经过一个化学性突触需要0.3~0.5ms(递质释放、弥散、与突触后膜受体结合及突触后膜离子通道开放等环节),反射通路中,经过的突触越多,需要的时间越长。
A. Were he to take B. Was he taken C. If he was to take D. Had he taken 参考答案:D 答案解析:考查虚拟语气的倒装结构。原句为:If he had taken up drawing,he would have become an outstanding painter.变为虚拟语气句的倒装结构时