词语填空。用方框中所给单词的适当形式填空，使短文通顺、正确、连贯(每个单词限用一次)。

danger  high  other  hundred  also  foot  in  them  that  climb

 Some people say the 小题1:you climb, the harder you fall. Those people probably wouldn’t be rock climbers.
There are about nine million rock climbers in the United States. Some do it just for fun. 小题2:compete (竞赛). Rock climbing can be 小题3:, but there are many ways 小题4:can protect climbers. They hope to challenge 小题5:through climbing.
There are several kinds of rock climbing. Traditional 小题6:is done outside. Climbers use ropes and equipment to climb many 小题7:of meters up. Sport climbing is similar. There is 小题8:indoor climbing. Rock walls made of wood or concrete(混凝土) have places for climbers’ hands and 小题9:.
Nowadays, many American teenagers take part 小题10:the activity of rock climbing. It is a great way to build their confidence and strength.