2013年4月20日，四川省雅安市芦山县发生了7.0级地震，某校开展了“雅安，我们在一起”的赈灾捐款活动，其中九年级二班50名学生的捐款情况如下表所示：

勤奋和善于钻研是牛顿的性格，有人评价他在大学时代取得的某项成就时说：“即使牛顿没有别的成就，仅这个也足以使他在科学史上留下不朽之名。”该人所评价的牛顿的成就是

    Two farmers were on their way home one evening after a hard day's work．Both were tired．They happened to look up at the sky and saw a black cloud overhead．
    "Ah!" said one farmer, "tomorrow we shall have rain and the rice will grow well．" The second answered, "Nonsense （胡说）, the rain will only kill the crops （庄稼）．"
    So they began to fight．Just then a third farmer came along and asked them why they were quarreling（争吵）．Both farmers explained about the black cloud．
    "What cloud?" asked the third farmer．They all looked at the sky．The cloud was no longer there．