按（）键使用画圆或画矩形放假，可以绘制出正圆或正方形
A.Shift
B.Ctrl+Shift
C.Alt
D.Tab+Shift
参考答案：A
- In our English study reading is more important than speaking, I think.
- I don’t agree. Speaking is _______ reading. [ ]
A. as important as
B. so important as
C. the most important
D. not as important as
圆截面细长压杆的材料和杆端约束保持不变，若将其直径小一半，则压杆的临界压力为原压杆的（）。
A．1/2
B．1/4
C．1/8
D．1/16
