During the long history of mankind,people have made thousands and thousands of inventions． Some of t

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During the long history of mankind,people have made thousands and thousands of inventions． Some of them are very important,while others are less important． Do you know what is the first real invention?Man"sfirst real invention,and one of the most important inventions in history was the wheel． All transportation and every machine in the world depend on it． The wheel is the simplest yet perhaps the most remarkable of all inventions,because there are no wheels in nature— no living thing was created with weels． How,then,did man come to invent the wheel?Perhaps some early hunters found that they could roll the carcass（兽尸）of a heavy animal through the forest on logs more easily than they could carry it． however,the logs themselves weighed a lot． It must have taken a great prehistoric（史前的） thinker a long time to imagine two thin slices（pieces）of log divided at their centers by a strong stick． This would roll along just as the logs did,yet by much lighter and easier to handle（操纵）． Thus the whe

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