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【单选题】
四杆机构中,连架杆的长度分别用a、c表示,机架的长度用d表示,连杆的长度用b,则下列四杆机构中有曲柄的四杆机构是( )。A.
a=20 ；b=20 ；c=80 ；d=50
B.
a=20 ；b=30 ；c=80 ；d=40
C.
a=20 ；b=50 ；c=80 ；d=60
D.
a=20 ；b=30 ；c=80 ；d=45
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【简答题】世界上第一台电子数字计算机是1946 年诞生在（）国。
【单选题】In the early of 19th Century, Britain was the "____________" as the result of the Industrial Revolution
A.
Workshop of the World
B.
Financial Center of the World
C.
Economical Engine of the World
【单选题】In the early of 19th Century, Britain was the "____________" as the result of the Industrial Revolution
A.
Workshop of the World
B.
Factory of the World
C.
Economical Engine of the World
【判断题】The Industrial Revolution was accomplished in Britain by the middle of the 19th.
A.
正确
B.
错误
【判断题】The Industrial Revolution first took place in Britain mainly from the middle of the 18 th century to the middle of the 19th century then spread to the other countries in the world.
A.
正确
B.
错误
【简答题】看课本,并完成课后题。完成后拍照上传。
【简答题】()就是由若干动力车和拖车或全部由动力车长期联挂在一起组成的车组。
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