---I can't work out the math problem, what should I do?
---You can turn to the teacher.
记不等式组x≥0x+3y≥43x+y≤4所表示的平面区域为D.若直线y=a(x+1)与D有公共点,则a的取值范围是____ .
以下属于可再生资源的有( )