写作思路：首先描述一下体育锻炼给人们带来的好处，再描述一下自己或者在学校都参加了什么体育运动等等。
正文：
Physical exercise is conducive to the growth of human bones and muscles, making the bones solid.Physical exercise can improve the function of blood circulation system, respiratory system and digestive system, which is conducive to the growth and development of human body, improve disease resistance and enhance immunity.
体育锻炼有利于人体骨骼、肌肉的生长，使骨骼变得坚实。体育锻炼能够改善血液循环系统、呼吸系统、消化系统的机能状况，有利于人体的生长发育，提高抗病能力，增强免疫力。
Sports in Our School Sports in our school have changed a lot．Now we have more than three P．E．classes a week．And we have at least one hour to exercise every day． Students get so excite at these changes More and more students take an active part in the ball game．Running and jumping on the playground．
我们学校的体育运动发生了很大的变化。现在我们每周有三节以上的体育课。我们每天至少有一个小时的时间锻炼。学生们对这些变化非常兴奋。越来越多的学生积极参加球类运动。在操场上跑和跳。
Our school life is becoming more wonderful． Doing sports is a good way to relax and keep fit．What’s more a healthy body can help us study better and live a happier life．
我们的学校生活变得越来越美好。运动是放松和保持健康的好方法。更重要的是，健康的身体可以帮助我们更好地学习和生活得更快乐。