—____(Who , What ) is that boy ?
— He's Eddie .
已知4x=3y,求代数式(x﹣2y)2﹣(x﹣y)(x+y)﹣2y2的值.
如图所示,当闭合开关S,且将滑动变速器的滑片P向左移动时,电磁铁( )