根据图中小磁针静止时的指向,请在图中标出螺线管的S极和电源的正极.
解:小磁针N极向右,则得螺线管左侧为S极,右侧为N极,由安培定则得电流由右侧流入螺线管,即电源左侧为正极,右侧为正极.如图所示:
— Because they are waiting to watch the boat races.
⑴____ A.large B.age C.GermanD.ground
⑵____ A.school B.change C.cheap D.teacher
⑶____ A.headacheB.ChristmasC.machine D.school
⑷____ A.what B.whole C.which D.White
⑸____ A. warm B. parcel C. charcoal D. far