下列四个命题中正确的是（ ）①若一个平面内的两条直线与另一个平面都平行，那么这两个平面相互平行；②若一个平面经过另一个平面的垂线，那么这两个平面相互垂直；③垂直于同一直线的两条直线相互平行；④若两个平面垂直，那么一个平面内与它们的交线不垂直的直线与另一个平面也不垂直．
A：①和②
B：②和③
C：③和④
D：②和④
They went to the museum ____Sunday morning.
Our class _______ forty-five students, in other words, forty-five students ______ our class.
His comprehensive surveys have provided the most _________ statements of how, and on what basis, data are collected.
