23、Mr. Simpson worked in a shop which sold, cleaned and repaired hearing-aids（助听器）. One day an old gentleman entered and put one down in front of him without saying a word.
"What's the matter with it?" Mr. Simpson said. The man didn't answer. Of course Mr. Simpson thought the old man must be deaf and that his hearing-aid must be faulty, so he said again, more loudly, "What's wrong with your hearing-aid, sir?" Again the man said nothing. So Mr. Simpson shouted his question again as loudly as he could.
The man then took a pen and a piece of paper and wrote: "It is not necessary to shout when you are speaking with me. My ears are as good as yours. The hearing-aid is my wife's, not mine. I've just had a throat（咽喉） operation, and my problem is not that I can't hear, but that I can't speak."