球叉式万向节有5个钢球都传力,球笼式万向节有6个钢球都传传力。( )
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现代行星齿轮自动变速器和普通圆柱齿轮手动变速器的变速机理一样,都是通过改变齿轮啮合实现传动比改变的。( )
A. 对
B. 错
变速器传动机构的主要作用是改变转速、转矩的大小、方向。( )
A. 对
B. 错
In most circumstances , it’s not necessary for us to stand up to greet a visitor if he or she is a ( n ) .
A. applicant
B. exception
C. professional
D. complainant
In order to hold more and more cars , the parking lot in this community has been .
A. found
B. expected
C. extended
D. founding
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