Mr. Chen was puzzled（闲惑的）and a little suspicious（怀疑的）. He sat in the office and studied a letter apparently（看似）from Mrs. Wang, the mother of one of the pupils in his class. There was something about it which worried him.
"I don't understand," he said to himself. He shook his head as he circled four mistakes in the letter. "Mrs. Wang is an educated woman. She wouldn't make mistakes like these even if she did write the letter in a hurry. "Mr. Chen took out his class register(名册)and said to himself, "Yesterday was Thursday. Let me see. Ah, yes. I thought so. David was absent on Thursday last week and the week before. Hm. Why is he so often absent on Thursdays? Was he really ill yesterday? Could it be a coincidence(巧合)?”
Mr. Chen stared at the register as if the answers to his questions were hidden in it somewhere. Then he took out a copy of the timetable(课程表)for his class.
"I wonder." he told to himself. "I wonder if his absence has anything to do with one of these lessons."
Mr. Chen looked at the subjects for Thursday: Mathematics, English, P. E. He thought about P. E. He knew that the pupils had P. E. twice a week: once on Monday, when they usually played games on the school field, and once on Thursday, when they did exercises in the gym.
Mr. Chen glanced round the office to find Mr. Long, the rather strict P. E. teacher, but he was not there.
"I'd better have a chat with Long and David, "Mr. Chen thought.
The bell rang. "I can't do anything right now," Mr. Chen thought. "It's time to go to Class 2. I'll do it later on."
Mr. Chen picked up his books and walked off to teach Class 2.
Later, on Friday, Mr. Chen spoke to Mr. Long, the P. E. teacher. Mr. Long agreed that it seemed strange for David to be absent so often on gym days. They thought about it for a while.
"David is a good athlete(运动员)," Mr. Long finally said, "but he's afraid of heights. I was hard on him once because he wouldn't climb more than a couple of meters up the rope. Do you think that's why he's been absent recently?"
"Yes, I think so," Mr. Chen said. "I'm going to talk to him this afternoon before he goes home."
"Well, I've got a suggestion to make," said Mr. Long. "If he's scared of heights, he'd better come and see me after school. Quite a few people suffer from (遭受) vertigo. I'll be glad to help him."
“That's very kind of you," said Mr. Chen. "I'll get him to come and see you on Monday or Tuesday."
