题目

语法填空Buy, buy in Bangkok The city of angles is a divinedestination for those who are in heaven when they shop, spa and eat, accordingto a report by China Daily. Even if you are just in townfor a few days, (shop) in Bangkok is an experience not to bemissed. From air-conditioned malls to cheerful markets, you have a trip made inheaven for those like to keep the swings open. It is in Central Bangkok you will also find the tempting delights andwelcoming chilled (休闲舒适的)interiors of refined palacesof luxury consumption such as Central Chidlom, which has a one-stopshopping philoso已知函数f（x）=-xm，且f（4）=-．（1）求m的值；（2）判断f（x）在（0，+∞）上的单调性，并给予证明．