如图,某广场一角的矩形花草区,其长为40m,宽为26m,其间有三条等宽的路,一条直路,两条曲路,路以外的地方全部种上花草,要使花草的面积为864m2,求路的宽度为____m.
His family are worried about him because they haven't __________ letters from him for a long time.
如图所示图像,不能表示一定条件下哪组物理量之间的关系 ()