A:had they
B:they could
C:could they
D:did they
My brother doesn't like playing basketball __________ watching TV.
如图所示,是小明“探究感应电流实验条件”的实验装置.
(1)他将金属棒AB紧贴金属支架向右滑动时,AB将产生电流,这种现象叫____ .同时,轻巧的金属棒CD会向右摆动,CD运动的道理与____ (选填“发电机”或“电动机”)的原理是相似的.
(2)如图保持AB不动,将甲磁铁向左移动,AB也会产生电流,电流的方向与前次____ (选填“相同”或“相反”),CD会向____ (选填“左”或“右”)摆动.
已知两点A(1,1),B(5,4),若向量a→=(x,4)与AB→垂直,则实数x=____
读某城市略图,完成下列问题。