呼吸器官障碍性呼吸衰竭主要表现为
A．吸气困难
B．呼气困难
C．呼吸节律不整
D．呼吸减慢
E．辅助呼吸肌补偿活动增强
参考答案：E
—When__________ you __________ your homework?
—I had finshed it before my mother ___________back. [ ]
A. have; finished; came
B. have; finished; was coming
C. did; finish; came
D. did; finish; was coming
一般而言，流行病学认识疾病的途径是（）
A.从群体水平认识疾病
B.从细胞水平认识疾病
C.从分子水平认识疾病
D.从个体水平认识疾病
E.从基因水平认识疾病
