若一个多边形的内角和是外角和的3.5倍，则此多边形的边数是______．
设所求正n边形边数为n，
则360°×3.5=（n-2）•180°，
解得n=9．
—It has been written into law that drink driving can be a crime(罪).
—I quite agree. We should better be careful not to _____________the law.
A．test
B．cheat
C．break
D．deal
水泥的初凝时间是从水泥加水拌合起，至水泥浆完全失去可塑性并开始产生强度所需要的时间。( )
