生物源农药
参考答案：直接利用生物活体或生物代谢过程中产生的具有生物活性的物质或从生物体提取的物质作为防治病虫草害的农药。
若对于任意实数x，不等式|x+2|-|x-1|＞a恒成立，则实数a的取值范围是______．
______ has recently been done to improve the conditions of elementary schools, a great number of children are unable to go to school.
A．That
B．What
C．In spite of what
D．Though what
