第1题: [单项选择]老年人的脉压差较青年人为大，这主要是由于 A. 老年人的心输出量较少 B. 老年人的循环血量较少 C. 老年人的主动脉和大动脉弹性降低 D. 老年人的小动脉弹性降低 参考答案:C 答案解析:[考点] 影响脉压差大小的因素 [解析] 正常情况下，大动脉的弹性是影响脉压差大小的因素之一。老年人的主动脉和大动脉由于管壁发生粥样硬化，使弹性降低，对血压的缓冲作用降低，使收缩压升得很高，
第9题: [单项选择]Questions 11 to 18 are based on the conversation you have just heard. A. Stay away for a couple of weeks. B. Check the locks every two weeks. C. Look after the Johnsons’ house. D. Move to anoter place. 参考答案:A 答案解析:[听力原文] W: Did you turn off the lights and check the locks on all the doors M: Yes, I told the
第12题: [单项选择]Thousands of people are packed tightly in trains, the men's faces ______ in their evening papers, while the women trying in vain to knit. A. burying B. buried C. to bury D. being buried 参考答案:B 答案解析:名词和过去分词构成的独立主格结构
第31题: [单项选择]If a student doesn't understand an important part of the lesson, he or she__________. A. will never be a good student B. should ask another student for class notes C. should get a perfect score D. should ask the instructor to explain it 参考答案:D
