函数f(x)=|4x﹣x2|﹣a有四个零点,则a的取值范围是____ .
不符合下图中的大圆、中圆和小圆依次所代表的地理概念是( )
已知分式x-12-3x,x取哪些值时:
(1)分式无意义;
(2)分式的值是零;
(3)分式的值可以为-13吗?
—So it is. It's made _______ grapes, and they can be made _______ many other foods.