阅读理解，选择正确的答案。

Old Jack goes to see a doctor．The doctor looks over(检查)him carefully and says，"Medicine can't help you．You must have a good rest．Go to a quiet place for a month．Go to bed early，drink some milk，walk a lot and smoke one cigar(抽一支雪茄烟) a day. "Thank you very much，"says old Jack．"I can do everything you say．''

Four weeks later，Old Jack comes to the doctor again．"Well，"says the doctor．"I am glad to see you．You look much younger．''

"Oh，doctor，"says Old Jack，"I feel quite well now．I have a good rest．I go to bed early．I drink a lot of milk and walk a lot．Your advice(建议)helps me．But you ask me to smoke one cigar a day，and it nearly kills me at first．It is no joke(笑话)to smoke at my age．"