用40cm长的绳子围成一个平行四边形，使其相邻两边的长度比为3：2，则较长边的长度为____ cm．
— There's somebody at the door. Who ____ it be? Is it the postman?—No. It ______ be him. It's just seven o'clock. It's too early.
已知f（x）=xlnx﹣ax，g（x）=x3﹣x+6，若对任意的x∈（0，+∞），2f （x）≤g′（x）+2恒成立，则实数a的取值范围为（ ）
81－68=____
