题目

    Almost half of us live in a city these days, and that number keeps going up. Want to be healthy? Try to make the best use of your city. Walk the Walk: We know city people usually walk more than country people. But you'd be surprised at how much those extra 15 to 30 minutes of walking can do you good.   Get Arty: Cultural attractions is something most cities are rich in. So if you’re in the city, refuse the pricy bar and club. Your brain will thank you if you choose from one of the countless museums, theatres, art galleries and historical sites (古迹). Meet the Neighbors: St定义：若函数在某一区间D上任取两个实数、，且，都有，则称函数在区间D上具有性质L。（1）写出一个在其定义域上具有性质L的对数函数（不要求证明）。（2）对于函数，判断其在区间上是否具有性质L？并用所给定义证明你的结论。（3）若函数在区间（0，1）上具有性质L，求实数的取值范围。