题目

        Is beauty something always positive? Almost everyone thinks attractive people are happier and healthier, have better marriages and have more respectable jobs. Personal advisors give them better advice for finding jobs. Even judges are softer on attractive defendants. But in the executive（主管的） circle, beauty can become a disadvantage. While attractiveness is a positive factor for a man on his way up the executive ladder, it is harmful to a woman. Handsome male executives were considered having more honesty than plainer men; effort and ability were thought to lea 在图中，开关S断开时，小磁针静止在图甲所示的位置；开关S闭合时，小磁针静止在图乙所示的位置．由此可知 [　　] A．a端是电磁铁N极，c端是电源正极 B．a端是电磁铁N极，c端是电源负极 C．b端是电磁铁N极，d端是电源正极 D．b端是电磁铁N极，d端是电源负极