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      A well-known old man was being interviewed and was asked if it was correct that he had just celebrated his ninety-ninth birthday.

     “That's right.” said the old man. “Ninety-nine years old, and I haven't an enemy in the world. They're all dead.”

  “Well, sir,” said the interviewer, “I hope very much to have the honour of interviewing you on your hundredth birthday.”

     The old man looked at the young man closely, and said, “I can't see why you shouldn't look fit and healthy to me!”

食用加碘食盐、提倡使用铁锅、多吃水果和蔬菜可分别预防（　　）

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