五四运动中学生提出的斗争口号初步实现的有()
①外争国权,内惩国贼
②誓死力争,还我青岛
③废除二十一条
④拒绝和约签字
A.①②③
B.①④
C.①③④
D.①②③④
参考答案:B
.
—___________ is the population of the United States?
—I don’t know exactly, but I’m sure that it has __________ population than China.
A.How much; much less
B.How many; fewer
C.What; much less
D.What; a much smaller
如图所示,用铝板制成“U”形框,将一质量为m的带电小球用绝缘细线悬挂在框的上方,让整个装置在水平方向的磁场中向左以速度V匀速运动,若悬线拉力为F,则
A.悬线竖直,F=mg
B.悬线竖直,F<mg
C.适当选择V的大小可使F=0
D.因条件不足,F与mg的大小关系无法确定