Playgrounds in schools and parks are usually built to be safe enough． Most of the safety rules were created（1）　　 the 1980s， after a few accidents happened on playgrounds． Some children were hurt（2）　　 （serious） in these accidents． Their parents said the playgrounds weren't safe enough， and that the bosses that owned the playground（3）______　（have） to pay much money to those parents． After that， schools and cities began changing playgrounds to make them as safe（4）　　 possible．

    But safe playgrounds have not really made a（5）　　 （different） in the accidents． In fact， there have been more accidents where children have broken an arm or a leg． Some experts believe that this is because children can learn to be careful only（6）　　 they are in danger．

    Children should do things that seem a little dangerous﹣﹣﹣like climbing trees， riding bikes really fast or playing near water． Those things can teach（7）　　 （they） how to keep safe． When children have small accident， they learn how（8）　　 （avoid） worse accidents．

    If children（9）　　 （allow） to take some risks， they can become confident and independent．They also get better at problem﹣solving and teamwork．

    Many experts also believe that "safe" playground are too boring． They say that if playgrounds were more challenging and（10）　　 （excite）， kids would probably get more exercise．