单选题 Man's first 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 ever created with wheels. How, then, did man come to invent the wheel? Perhaps some early hunters found that they could roll the carcass 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 thinker to imagine two thin slices of log connected, at their centers by a string stick. This would roll along just as the logs did, yet be much lighter and easier to handle. Thus the wheel and axle came into being and with them the first carts.

单选题 The wheel is important because ______.

A. it was man's first real invention
B. all transportation depends on it
C. every machine depends on it
D. both B and C

【正确答案】 D

【答案解析】[解析] 参考文章第二句。

单选题 The wheel is called ______.

A. simple
B. complicated
C. strange
D. unusual

【正确答案】 D

【答案解析】[解析] 参考文章第一段，其中说到，“轮子在自然界中是不存在的”，所以最能说明轮子的就是“unusual”。

单选题 It was remarkable of man to invent the wheel because ______.

A. it led to many other inventions
B. man had no use for it then
C. there were no wheels in nature
D. all of the above

【正确答案】 D

【答案解析】[解析] 参考文章第三句because后的部分。

单选题 The wheel was probably invented by ______.

A. a group of early hunters
B. the first men on earth
C. a great prehistoric thinker
D. the man who made the first cart

【正确答案】 A

【答案解析】[解析] 参考文章第五句。