【单选题】The external circumference of a pair of main bearing shells is slightly larger than that of the bore of the housing which receives themThe difference is termed _____.
【单选题】The external circumference of a pair of main bearing shells is slightly _____ that of the bore of the housing which receives themWhats the meaning of “that” in the sentence above?
【单选题】已知椭圆 x 2 4 + y 2 b 2 =1 (0<b<2)与y轴交于A、B两点,点F为该椭圆的一个焦点,则△ABF面积的最大值为( )
【单选题】已知F 1 ,F 2 是椭圆 x 2 a 2 + y 2 b 2 =1(a>b>0) 的两个焦点,AB是过F 1 的弦,则△ABF 2 的周长是( )
【单选题】已知点M(-1,2)在直线2ax-by+2=0(a>0,b>0)上,则 4 a + 1 b 的最小值是( )
【单选题】已知抛物线x 2 =ay(a>0)的焦点恰好为双曲线y 2 -x 2 =8的焦点,则a=( )
【简答题】已知点 A(-1,8),B(2,4),则 ∣AB∣=
【判断题】离心泵通过离心力的作用来输送和提升水体。靠高速旋转的叶轮带动叶轮中的水作圆周运动,产生离心力,水流在离心力的作用下获得压能而输送出去。( )
【单选题】The bearing shells depend on the accuracy of__to hold them in truly circular shape accuracy精确度
【单选题】已知过点A(-2,m)和B(m,4)的直线与直线2x+y+1=0平行,则m的值为