I'm very hungry. Please have some __________.
A:milk
B:rice
C:orange juice.
读《鱼,我所欲也》,“非独贤者有是心也,人皆有之,贤者能勿丧耳。”中的“是心”是指____
如图所示,直导线MN中通有M向N的电流,要使闭合导线圈a中产生如图方向的感应电流,应采取的办法是( )