Dear Mary，

  I'm sorry to hear that you have been ill for days and hope you have got better now. You have studied so hard that you have had no time for exer?cise. This is harmful for your health. You have been in poor health these years. I feel it would be more beneficial to your health if you could take more exercise in future.

  Do not think that time spent in exercise is wasted. Exercise can improve your physical con?stitution and refresh the mind. After one or two hours of exercise you can study better. Only when you have a strong body can you keep on studying without feeling fatigue. Otherwise your study will be interrupted from time to time by fatigue or sick?ness.

  I'm not advising you to devote all your time to exercise. What I want to say is that exercise is as useful and important as your study. I hope you can take at least one hour's exercise every day af?ter you are recovered. I would be more than happy to see you have a stronger body.

                              Sincerely yours John

Dear Mary，

  I'm sorry to hear that you have been ill for days and hope you have got better now. You have studied so hard that you have had no time for exer?cise. This is harmful for your health. You have been in poor health these years. I feel it would be more beneficial to your health if you could take more exercise in future.

  Do not think that time spent in exercise is wasted. Exercise can improve your physical con?stitution and refresh the mind. After one or two hours of exercise you can study better. Only when you have a strong body can you keep on studying without feeling fatigue. Otherwise your study will be interrupted from time to time by fatigue or sick?ness.

  I'm not advising you to devote all your time to exercise. What I want to say is that exercise is as useful and important as your study. I hope you can take at least one hour's exercise every day af?ter you are recovered. I would be more than happy to see you have a stronger body.

                              Sincerely yours John