根据短文内容和所给的中文提示，写出空白处各单词的正确形式，每空限填一词。
I am a middle school student and I'm  小题1:  (十五）years old, I’m quite healthy.     小题2:   (然而）, one year ago I was fat. I loved chips and chocolate, and I got tired   小题3: （容易地）. One morning, I saw some young men running in the park. They looked really fit and ___小题4:____(积极的) . So I started running from   小题5: （那时）on .
Now I have a 1.5-mile run every morning, I   小题6:  ( 喝 ) milk and eat fruit and vegetables____小题7:______(代替) of chips and chocolate. These good eating habits and running help to build me up. I have great fun running. I feel well and look fit. Running has    小题8:   (成为) my favorite sport, I'm    小题9: （确信）I will do well in the boys' 800-metre race in our school sports meet.
If you want to be healthy,    小题10: （加入）us !