What's the coolest kind of transportation for middle school students back from the winter holidays?A racing bike?A car?No,it's a special 1 of shoes called Heelys(暴走鞋).Heelys look just like common 2 shoes,but they have a wheel hidden in the heel(鞋跟).So instead of 3 ,kids can"fly”around in them. "Wearing Heelys is fun and 4 ,"said Wu Peng,a boy who wore them on his 5 day back at No.6 Middle School in Beijing. Wu Peng said he loves the shoes so much that he wears them wherever he goes. Sometimes he even 6 his parents'car to the supermarket on his Heelys! Other students think these are very cool, 7 some haven't been so lucky with their Heelys. It's reported that some 8 have fallen down while using these shoes, and some have been hurt. “Heelys wheels are on the heels of the shoes,so it's 9 to fail,"said Liu,Rui,a doctor of the Hong Kong International Medical Clinic,Beijing.Even 10 , Liu said, "wearing Heelys for a long time could stop young people from developing their ankles and legs."