深入贯彻落实发展观的核心是（）
A.发展
B.以人为本
C.教育
D.经济
参考答案：B
Great changes have taken place in that school. It is no longer it was 20 years ago, it was so poorly equipped.
A．what; when
B．that; which
C．what; which
D．which; that
我国现用的三相电源中的任意二相线之间的电压为（）.
A.380V
B.220V
C.440V
D.0V
