心源性休克最常见的病因是（）
A.急性广泛心肌梗死
B.重症心肌炎
C.严重心功能不全
D.急性心包填塞
E.心房粘液瘤
参考答案：A
—What _____ your father and mother ____?
—They are teachers, and they work in our school.[ ]
A. are, does
B. do, do
C. are, do
D. do, does
下列杠杆中，属于省力杠杆的是（ ）
A．
起子
B．
道钉撬
C．
镊子
D．
筷子
