阅读理解
Mick Polly，an owner of a toy store，lives with his teenage daughter Carolina in Kentucky．He is known as the Bike Man．Over the past five years，Mick has built hundreds of bikes for needy kids．
One day in 2012，a 13﹣year﹣old boy with a broken bike walked by Mick's house．"I was working in my garage（车库），and he asked if I could fix it，"says Mick，now 53．
The boy's bike had a broken wheel．Mick sent a post（帖子） on Facebook，asking his friends if they had the needed part．One friend saw the post and gave away two used bikes．Mick took parts from each to build a new set of wheels for the boy．
Soon after，Mick repaired a bike for the boy's brother and fixed one for his sister．Word spread，and during the year，he had fixed up lots of bikes for local kids whose parents were not able to afford new ones．
"People are throwing away bikes day and night，"says Mick．
Mick puts the bikes and bike parts in his garage．"I take off the good tires or the handlebars or the seats and use them，"he says．
Up to now，the bike man has repaired hundreds of bikes and given away nearly 700newly repaired bikes．They're free，but the kids must agree to two things：They have to learn how to put waste things to good use and they have to try their best to study in school．
If a kid's grades are low，Mick requires a teacher's note"saying that you're doing your best，"Mick says．Mick also hopes the bikes will get kids off the sofa．"When I was growing up，we all rode our bikes，"he says．"Hopefully these kids can get some exercise．"
2SO3，并达到平衡。在这过程中，甲容器保持体积不变，乙容器保持压强不变，若甲容器中SO2的转化率为p%，则乙容器中SO2的转化率
