从明初废除丞相到清初增设军机处,这一变化表明( )
My neighbours used to give me a hand in time of trouble, was very kind of them.
如果幂函数y=xaa∈R图像经过不等式组4x-3y+4≥0x+y-6≤0y≥2表示的区域,则a的取值范围是( )