题目

One year our family decided to have a special celebration of Mother’s Day, as a token of appreciations for all the sacrifices that Mother had made for us. After breakfast we had arranged, as a surprise, to hire a car and take her for a beautiful drive in the country. Mother was rarely able to have a treat like that, because she was busy in the house nearly all the time.     But on the very morning of the day, we changed the plan a little, because it occurred to Father that it would be even better to take Mother fishing. As the car was hired and paid for, we might as well use it to在北方的冬季，常见的几种物态变化现象中，属于凝华的是（　　）A．室外冻冰的衣服变干B．房间窗户玻璃的内表面出现冰花C．湖面结了厚厚的一层冰D．正在跑步的人，口中呼出“白气”