【简答题】当两构件组成转动副时 , 其相对速度瞬心在 处;组成移动副时 , 其瞬心在 处 ; 组成滑动兼滚动的高副时 , 其瞬心在 。
【单选题】当两构件组成移动副时,其瞬心在( )处。
【简答题】阅读理解。 The American newspaper has been around for about three hundred years. In 1721, the printer James Franklin. Benjamin's older brother, started the New England Courant, and that was what we might r...
【单选题】根据下面 ,回答 53 ~56 题:D The American newspaper has been around for about three hundred years. In 1721, the printer James Franklin. Benjamin's older brother, started the New England Courant, and that was w...
A.
It is mainly about the stock market.
B.
It marks the beginning of the American newspaper.
C.
It remains a successful newspaper in America.
D.
It comes articles by political leaders.