光学平面仪是利用()远离工作的,主要用来检查导轨在水平平面和垂直平面内的直线度。
A.校准
B.自定
C.自准直
D.调配
参考答案:C
一个正方体的棱长是a,如果把棱长扩大2倍,它的表面积就扩大8倍.______.
The speech by the mayor of Shanghai before the final voting for EXPO 2010 is strongly impressed _____
my memory. [ ]
A. to
B. over
C. by
D. on