在同一圆内,圆的周长与直径的比是π:1.______.(判断对错)
设圆的直径为d,则:
πd:d=π:1;
故答案为:√.
I would have come to see you earlier, but I __________ too busy.
A.had been
B.were
C.was
D.would be
利用平均振幅能量准则计算出来的速度谱称为相关速度谱.