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Dreams of Flight The story of man's dream of flight, of his desire to reach the stars, is as old as mankind itself. According to Greek legend, Daedalus was the first man to fly. He and his son had been kept on an island, in order to escape, Daedalus shaped wings of wax (蜡) into which he stuck bird feathers. During their flight, his son flew too high and the sun melted the wax. He was drowned in the sea. The father was supposed to have continued his Night and reached Sicily, several hundred miles away. There is also an English legend of King Bladud who, during his rule in the ninth century B.C., used wings to fly. But his flight was short-lived and he fell to his death. The dream of flying continued, but in all the legends, the flier rose like a bird only to fall like a stone. It took hundreds of years that men flew up into the air and returned to earth safely. The first man to approach flying on a scientific basis was an Englishman who lived during the thirth century. He looked at the air about us as a sea, and he believed that a balloon could float on the air just as a boat did on water. Almost four hundred years later, an Italian priest applied his principle of air flight. He designed a boat, which would be held in the air by four hollow spheres (空心球). Each of the four balls was to be 20 feet in diameter (直径) and made of very thin copper. But his boat was never .built since it was not possible to make spheres of such thin metal and such size in those days. After studying the flight of birds and the movement of the air, a great scientist of the fifth century concluded that birds flew because they flapped (摆动) their wings and that it was possible for man to do the same. So a kind of flapping-wing flying machine was invented. Many men tried and failed to fly with flying machines. It was not until 1890 that people discovered why this method would never succeed-man could not develop sufficient power with his arms and legs. How did Daedalus manage to escape to Sicily, according to the passage?

A.
He killed the guards and got out of the island.
B.
A god came to rescue him and took him away.
C.
His son came to rescue him and took him away.
D.
He made wings of wax and flew away from the island.
题目标签:摆动空心球直径
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【单选题】管道的公称直径是指()

A.
内径
B.
外径
C.
与外径对应的直径系列范围
D.
内径与外径平均值

【单选题】全身直径最粗大,行程最长的神经是

A.
腓总神经
B.
坐骨神经
C.
胫神经
D.
正中神经

【多选题】传水辊传墨辊的摆动()。

A.
可以手动
B.
可随滚筒离合进行工作或停止
C.
只能自动进行
D.
不能手动
E.
不可随滚筒离合进行工作或停止

【单选题】成熟卵泡直径为:()

A.
8~10mm
B.
10~15mm
C.
12~18mm
D.
18~25mm
E.
22~30mm

【单选题】 前轮高速时摆动,则( )。

A.
前钢板弹簧刚度过小
B.
前轮过载
C.
车架变形
D.
前轮气压不足

【单选题】密码的摆动性是指( )。

A.
密码的三联体不间断,需要三个一组连续读
B.
一个氨基酸有2~4个密码子编码
C.
所有生物共用一套遗传码
D.
mRNA链上,碱基的插入或缺失
E.
密码的第三个碱基和反密码的第一个碱基和反密码的第一个碱基不严格配对

【单选题】纵隔摆动是指

A.
吸气时纵隔摆向患侧;呼气时移向健侧
B.
吸气时纵隔摆向健侧;呼气时移向患侧
C.
吸气时纵隔不动;呼气时移向健侧
D.
呼气时纵隔不动;呼气时移向患侧
E.
呼气时纵隔摆向健侧;呼气时不动
相关题目:
【单选题】管道的公称直径是指()
A.
内径
B.
外径
C.
与外径对应的直径系列范围
D.
内径与外径平均值
【单选题】全身直径最粗大,行程最长的神经是
A.
腓总神经
B.
坐骨神经
C.
胫神经
D.
正中神经
【多选题】传水辊传墨辊的摆动()。
A.
可以手动
B.
可随滚筒离合进行工作或停止
C.
只能自动进行
D.
不能手动
E.
不可随滚筒离合进行工作或停止
【单选题】轮在转向时是绕着( )摆动
A.
转向轴
B.
转向节
C.
转向柱
D.
主销
【单选题】成熟卵泡直径为:()
A.
8~10mm
B.
10~15mm
C.
12~18mm
D.
18~25mm
E.
22~30mm
【单选题】 前轮高速时摆动,则( )。
A.
前钢板弹簧刚度过小
B.
前轮过载
C.
车架变形
D.
前轮气压不足
【单选题】密码的摆动性是指( )。
A.
密码的三联体不间断,需要三个一组连续读
B.
一个氨基酸有2~4个密码子编码
C.
所有生物共用一套遗传码
D.
mRNA链上,碱基的插入或缺失
E.
密码的第三个碱基和反密码的第一个碱基和反密码的第一个碱基不严格配对
【单选题】纵隔摆动是指
A.
吸气时纵隔摆向患侧;呼气时移向健侧
B.
吸气时纵隔摆向健侧;呼气时移向患侧
C.
吸气时纵隔不动;呼气时移向健侧
D.
呼气时纵隔不动;呼气时移向患侧
E.
呼气时纵隔摆向健侧;呼气时不动