In a quiet classroom sat a professor in a white shirt and black pants. He was tall, had a serious face, and was slightly bald. He wore a pair of black glasses and looked very knowledgeable. When he stood up to speak, his expression became a little nervous. He took a deep breath and began to explain what he was going to teach today. His intonation was clear and smooth without any flaws. His body trembled slightly as if he was afraid of something. I couldn't help but be in awe of him because I knew he was a very talented professor and very strict with his students. The description of his appearance revealed his identity and personality. He was a serious and cautious professor, but also a little nervous and afraid.