The teacher walked into the classroom. He said, "Good evening, everybody." The students said, "Good evening, teacher." He walked over to his desk. He put his briefcase on his desk. He opened his briefcase. He took his notebook out of his briefcase. He took his books out of his briefcase. Suddenly, he felt dizzy. The room was spinning. He sat down. What was wrong with him? He put his hands on the desk. The desk was spinning. He closed his eyes. He opened his eyes. He didn't know what to do. What was wrong? He was sitting in his chair. But he felt like he was floating in air. How could he be floating in air? He sat in his chair for another minute. His students were talking to one another. They did not know how he felt. But he didn't tell them how he felt. He didn't say anything.