房性早搏( )
A．起源部位在心房B．起源部位在心室C．起源部位在交界区D．起源部位在窦房结E．起源部位在心肌
参考答案：A
社会心理学的形成期是（）。
A.哲学思辨阶段
B.学派时代
C.实证分析阶段
D.经验描述阶段
_____ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately.
A．Even if
B．As far as
C．If only
D．So long as
