正常情况下F波和M波的振幅比值为()
A.1%~3%
B.1%~5%
C.5%~10%
D.11%~15%
E.15%~20%
参考答案:B
先化简,再求值:﹣2(mn﹣3m2)﹣[m2﹣5(mn﹣m2)+2mn],其中m=1,n=﹣2.
行包运输站车交接有何规定?