I asked her ______.
A:how long she had the bike
B:how long did she have the bike
C:how long she bought the bike
D:how long did she buy the bike
已知线段AB=a,用直尺和圆规求作这条线段的黄金分割点C.
若方程:2(x-1)-6=0与1-3a-x3=0的解互为相反数,则a的值为( )
黄河中下游含沙量大的重要原因是( )。