下列哪项不是心悸伴昏厥或抽搐的常见病因()。
A.高度房室传导阻滞
B.阵发性室性心动过速
C.阵发性室上性心动过速
D.心室颤动
E.心房颤动伴Ⅱ度房室传导阻滞
参考答案:C
I _____ sight of an empty seat at the back of the bus and went directly there. [ ]
A. lost
B. caught
C. looked
D. took
仅对一方有利,对另一方无利也无害的种间共生关系称为______共生。