单选题
Miss Green was going to give a lesson on Monday afternoon. But on Sunday night she was told that she had to go to an important meeting the next day at exactly the same time. "No one can be in two places at the same time. What shall I do?" she thought. But soon, she had an idea. At five to three on Monday afternoon Miss Green went to the classroom. There were about twenty students waiting for her. "I'm sorry," she told them. "I won't be able to give my lesson today." The students looked surprised. Miss Creen went on, "I have an important meeting. But though I can't be with you, my voice can." Then she put a small tape recorder (磁带录音机) on the desk. "You see, I've recorded (录音) my lesson and you can listen to it without me." Thinking that she did the right thing, Miss Green turned on the recorder and left. The meeting finished a little early. Miss Green decided to go back to her students. She stood outside the classroom, listening to her voice. Then very quickly, she opened the door. To her surprise, the room was empty. As she looked around, she saw a lot of small recorders all "listening" to her lesson. "Well," she thought, "if I can be in two places at the same time, why can't they?/