秦朝建立中央集权制度的进步作用,不包括( )
A:有利于缓和阶级矛盾
B:有利于维护国家统一
C:促进了华夏文明的发展
D:有利于封建经济的发展
如果地球自东向西转,下列可信的是:( )
有两个电路元件A和B,流过元件的电流与其两端电压的关系如 图(甲)所示.把它们串联在电路中,如图(乙)所示.闭合开关S, 这时电流表的示数为0.2A,则电源电压和元件B的电功率分别是 ()
Flags have existed for over 3,000 years. The earliest flags were wooden or metal poles with a carving. About 2,000 years ago pieces of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important.
去年我省规划重建校舍约3876000平方米,这个数精确到十万位并用科学记数法表示为( )