格构式轴压柱等稳定的条件是()
A.实轴计算长度等于虚轴计算长度
B.实轴计算长度等于虚轴计算长度的2倍
C.实轴长细比等于虚轴长细比
D.实轴长细比等于虚轴换算长细比
参考答案:D
—I heard that Mr Smith found a way to fix our computer.
—Really? That was very _____ of him. [ ]
A. generous
B. clever
C. easy
D. necessary
写请批函、批答函,应采用()
A、命令式格式
B、文件式格式
C、信函式格式
D、会议纪要格式