天花板上挂三个轻质带电小球,相互作用如图所示,已知A球会被用毛皮摩擦过的橡胶棒所排斥,则另外两球的带电情况是:B带___________,C带____________。
负电;正电
左向右分流的先天性心脏病患儿的血流动力学改变是()。
A.肺血增多,体循环血量减少
B.肺血减少,体循环血量减少
C.肺血减少,体循环血量增加
D.肺血增多,体循环血量增加
E.肺动脉高压,肺血增多
Was it near the white building, if I may ask, __ __ Martin Luther King gave a speech "I have a dream"?
A.where
B.that
C.why
D.in which