题干

(1)条形磁铁磁性减弱了,小红采用如图1所示的方法增强它的磁性,请你在图中标出电源的“+”、“﹣”极和小磁针的N极.

(2)如图2所示,S1是光控开关,夜晚自动闭合,白天断开;S2是声控开关,有声音时自动闭合,安静时断开.请把图连接成声光控楼道节能照明电路.

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解:

(1)知道该螺线管左端是N极,右端是S极,由安培定则可知,电流从右侧流入,则电源右侧为正极;

据磁极间的作用规律可知,此时小磁针靠近螺线管左端N极的一定是S极,小磁针的右端一定是N极.如图所示:

(2)将光控开关、声控开关以及灯泡串联连接即可.如图所示:

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   Since finishing my studies at Harvard and Oxford, I've watched one friend after another land high-ranking, high-paying Wall Street jobs. As executives (高级管理人员) with banks, consulting firms,established law firms, and major corporations, many are now 1on their wayto impressive careers. By society's2, they seem to have it made.

   On the surface, these people seem to bevery lucky in life. As they left student life behind, many had a3drink attheir cheap but friendly local bar, shook hands with longtime roommates, and4out of small apartments into high buildings. They made reservations atrestaurants where the cost of a bottle of wine5a college year's monthlyrent. They replaced their beloved old cars with expensive new sports cars.

    The thing is, a number of them have6 thatdespite their success, they aren't happy. Some 7of unfriendly coworkers andfeel sad for eight-hour workweeks devoted to tasks they 8. Some do notrespect the companies they work for and talk of feeling tired and 9. However, instead of devoting themselves to their work, they find themselvesworking to support the10 to which they have so quickly become11.

     People often speak of trying a more satisfying path, and 12 in the end the idea of leaving their jobs to workfor something they   13 or finding a position that would give themmore time with their families almost always leads them to the same conclusion: it's14 . They have loans, bills, a mortgage(抵押贷款)to 15, retirement to save for.They recognize there's something 16in their lives, but it's 17to stepoff the track.

    In a society that tends to18 everything in terms of dollars andcents, we learn from a young age to consider the costs of our19infinancial terms. But what about the personal and social costs  20 in pursuing money over meaning? These are exactly the kinds of costsmany of us tend to ignore — and the very ones we need to consider most.