$\frac{7}{8}-\frac{3}{5}+\frac{1}{8}-\frac{2}{5}$ =____

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       Some thing in chocolate could be used to stop coughs and lead to more effective medicines,say UK researchers.

Theirstudy found that theobromine, found in cocoa, was nearly a third more effectivein stopping coughs than codeine, which was considered the best cough medicineat present.

    The   Imperial College London researchers who published their results online said thediscovery could lead to more effective cough treatment. “While coughing is notnecessarily harmful, it can have a major effect on the quality of life, andthis discovery could be a huge step forward in treating this problem，” said Professor Peter Barnes.

Tenhealthy volunteers were given theobromine, codeine or placebo, a pill thatcontains no medicine, during the experiment. Neither the volunteers nor theresearchers knew who received which pill. The researchers then measured levelsof capsaicin(辣椒素),which is used in research to cause coughing and as a sign of how well themedicines are stopping coughs.

Theteam found that, when the volunteers were given theobromine, the capsaicin needto produce a cough was around a third higher than in the placebo group. Whenthey were given codeine they need only slightly higher levers of capsaicin tocause a cough compared with the placebo.

   There searchers said that theobromine worked by keeping down a verve activity(神经活动), which caused coughing. They alsofound that unlike some standard cough treatments, theobromine caused no sideeffects such as sleepiness.

    初，武与李陵俱为侍中。武使匈奴，明年，陵降，不敢求武。久之，单于使陵至海上，为武置酒设乐。因谓武曰：“单于闻陵与子卿素厚，故使陵来说足下，虚心欲相待。终不得归汉，空自苦亡人之地，信义安所见乎?前长君为奉车，从至雍棫阳宫，扶辇下除，触柱折辕，劾大不敬，伏剑自刎，赐钱二百万以葬。孩卿从祠河东后土，宦骑与黄门驸马争船，推堕驸马河中溺死，宦骑亡，诏使孺卿逐捕，不得，惶恐饮药而死。来时太夫人已不幸，陵送葬至阳陵。子卿妇年少，闻已更嫁矣。独有女弟二人，两女一男，今复十余年，存亡不可知。人生如朝露，何久自苦如此！陵始降时，忽忽如狂，自痛负汉，加以老母系保宫。子卿不欲降，何以过陵？且陛下春秋高，法令亡常，大臣亡罪夷灭者数十家，安危不可知，子卿尚复谁为乎?愿听陵计，勿复有云。”武曰：“武父子亡功德，皆为陛下所成就，位列将，爵通侯，兄弟亲近，常愿肝脑涂地。今得杀身自效，虽蒙斧钺汤镬，诚甘乐之。臣事君，犹子事父也，子为父死，无所恨，愿勿复再言！”

    陵与武饮数日，复曰：“子卿壹听陵言！”武曰：“自分已死久矣！王必欲降武，请毕今日之，效死于前！”陵见其至诚，喟然叹曰：“嗟乎，义士！陵与卫律之罪上通于天！”因泣下霑衿，与武决去。