题目

One day, a middle school teacher comes into the classroom and says to his students, “Today I want you to write about yesterday’s football match. I'm going to take your exercise books home with me. Now please begin.” The students all take out their pens and exercise books and begin to write. A boy called Tom thinks hard（努力）. But he doesn't write down a word. Five minutes later, he finishes（完成）. He stands up and looks at the teacher. The teacher asks, “What is the matter, Tom?” “I have finished, sir.” says the boy. “Well, give me your book.” The boy goes to the 下列各图所示变化属于物理变化的是   A．石灰石与稀盐酸反应    B．加热水至沸腾     C．木炭在O2中燃烧　D．铁钉插入硫酸铜溶液