What can I do for you , young man ?   I need to rent three pairs of skates for the morning .   What sizes do you need ?   One pair of 37 , and two pairs of 21 . One for me , and the other two for two kids .   Here you are . And here are three crash helmets .   Thanks . Well , those two kids are beginners . What should I do about their safety ?   Well , there are a lot to do , but nothing to worry about . First , make sure they don't go far from the railings .   Oh , yeah , maybe I should ask them just to walk along the railings .   That's a good idea . And remind them to be slow at the beginning , not to run into the railings . 