发绀的决定性因素是（）
A.心脏有右向左分流
B.心功能衰竭
C.红细胞数量
D.血液中还原血红蛋白的绝对量
E.血压过低
参考答案：D
—How do you think of your visit to Qingdao?
—I enjoyed it. It was ________ than I expected.
A．far more interesting
B．even much interesting
C．very more interesting
D．a lot much interesting
休克患者，穿休克服(裤)的作用以下解释不恰当的是
A．可使生命器官的血液灌流得到改善
B．增加有效循环血量
C．可增加400～500ml的血液
D．压迫下半身，起自体输血的作用
E．有助于下肢出血的止血
