昏厥的原因
A.流出道梗阻、肺动脉狭窄B.脑血栓C.心力衰竭D.中毒性脑病E.低钙惊厥
参考答案:A
Many animals sleep a lot when young, but sleep much less when they get older, just________is the case with human being.
A.as
B.which
C.what
D.it
能使阻尼孔两端产生压差的是()。
A.静止液体
B.高压液体
C.低压液体
D.流动液体