I don't know _____.[ ]
A. where is the pen
B. where does the pen
C. where the pen is
答案:C
计算基底压力有何实用意义?如何计算中心及偏心荷载作用下的基底压力?
若积分环节时间常数为T,则输出量随时间的增长而不断地增加,增长斜率为()
A.T
B.1/T
C.1+1/T
D.1/T2