题目

There used to be hundreds of red squirrels in the British forest. Every year, lots of 【1】 (tour) went there to watch them. But now they have become endangered and there are fewer than 160,000 red squirrels【2】（live） in the forest. And most of them are in Scotland. However, gray squirrels are now so common in Britain 【3】 so many people don not like them. Some people even think they should kill gray squirrels for the 【4】 (protect)of the red squirrels.You can hardly notice the 【5】 (different) between two kinds of squirrels when you see them for the first time. They both hav二次函数的值恒小于0，则m的取值范围是___________。