⊙O中，直径AB=a，弦CD=b，则a与b大小为（ ）
A．a＞b
B．a≥b
C．a＜b
D．a≤b
直径是圆中最长的弦，因而有a≥b．
故选B．
How ______ you did so much work with such a short time?
A．did it come about
B．did it come about that
C．came about that
D．was it that came about
吸附塔压力低低联锁值是（）。
A、0.2MPa
B、0.25MPa
C、0.3MPa
D、0.35MPa
