年真题The history of transportation is very long and full of changes and inventions. It starts________walking, which is not any invention;it just takesenergy.Peopleusedtowalktogettootherplaces.Ifyouwantedto get somewhere quickly, the________way to do that was to run. Actually,the first invention for transportation________was the shoe. Centuries ago there were no shoes, andpeople walkedbarefoot.Then people invented________to transport themselves and materials from one place toanother.In some culture, people invented sledges(雪橇),________are a kind of board that you drag along the ground.Youcan tie things on the sledge tohelp carry them, but it's a challenging invention________if you hit a rock with the sledge as you pull it, the contents can________.In other cultures, people invented the wheel, which they used to make it easier to move things and people. That was the beginningof many innovations in transportation.