n.蹦极；过度操纵防止器；橡皮筋；松紧绳
It's the only reason bungee jumping exists. 这就是蹦极跳运动出现的惟一原因。
Someone tied a bungee cord to himself one day and jumped off of a very tall bridge. 某天某人用橡皮筋套住自己，然后从一个很高的桥上跳下。
n.蹦极
