Human beings enjoy challenges£®Many of them like physical challenges£®They ask themselves    l   £ºHow fast can I run? How high can I climb? How deep can I dive? How far can I swim? How long can I hold my    2   ?£¬they like to play    3   £®They like climbing£¬running£¬diving£¬lifting£¬jumping£¬and so on£®    4   £® four years millions of people all over the world enjoy the international sports    5    called Olympics and watch other people play sports How much can I lift? How high can I jump? Because people enjoy challenges like these