a:what is the meaning of doing exercise?
b:it is benefit to our body and heart health.
c:let us doing exercise together!
b:let us go.可不可以再加一些情景进去呢?谢谢了开始的时候，两人相遇，b在跑步，a在路上遇见。a：hei ,what are you doing?b：of course ,i am doing exercise!接着就是上面的对话了。