能使缩宫素分泌增加的有效刺激因素是（）
A.排乳增加
B.子宫颈扩张
C.催乳素水平升高
D.细胞外液量减少
E.血浆渗透压升高
参考答案：B
It is the interaction between people, rather than the events __ occur in their lives, __ is the main focus of social psychology.
A．that, that
B．that, which
C．which, which
D．that, what
