题目

    The Homeless Hero For many, finding an unattended wallet filled with £400 in cash would be a source（来源）of temptation（诱惑）. But the    16    would no doubt be greater if you were living on the streets with little food and money. All of this makes the actions of the homeless Tom Smith    17    more remarkable. After spotting a    18    on the front seat inside a parked car with its window down, he stood guard in the rain for about two hours waiting for the    19    to return. After hours in the cold and wet, he    20     inside and pu将甲、乙、丙三支试管按要求处理（加 入馒头是等量的）后放入37℃的左右温水中，5——10分钟后各滴入2毫升碘液，其结果分析正确的是A．三支试管均变为蓝色 B．三支试管均不变色C．甲试管变蓝色，乙试管变浅蓝色，丙试管不变色D．甲试管变蓝色，乙试管和丙试管不变色