如图所示电路,电源电压保持不变.闭合开关S,缓慢移动滑动变阻器的滑片P,电流表A1的示数逐渐变小,这一过程中( ) A.滑片P是向左滑动的B.电
请根据通电螺线管附近静止小磁针的指向,在图中括号内标出电源正、负极.
—How long do you think it is ________Mr Shao came to this school? —For about three years. A.when B.since C.before
与向量a=(1,-3,2)平行的一个向量的坐标为( )A.(1,3,2) B.(-1,-3,2)C.(-1,3,-2) D.(
如图,在正方形ABCD中,点E是对角线AC上一点,且CE=CD,过点E作EF⊥AC交AD于点F,连接BE. (1)求证:DF=AE; (2)当AB=2时,求BE2的值.
The two ladies are _______ the same age, but there seems to be ten years _______ them. A. at; between B. about; among C. as; among D. of; between
小明用100元钱去购买笔记本和钢笔共30件,已知每本笔记本2元,每支钢笔5元,那么小明最多能买( )支钢笔.A.11 B.12