下列不属于心脏传导系统的是
A．窦房结B．房室结C．冠状窦D．浦肯野纤维E．结间束
参考答案：C
—How's my father, doctor?
—I'm sorry to say he's _ [ ]
A. much better
B. very well
C. more worse
D. even worse
社会保障制度的历史至今已有______。
A．50多年B．80多年C．100多年D．150多年
