-3的相反数是(  )

阅读理解
B
    Hello!I'm Kate．I want to talk about my smart phone(智能手机)．My smart phone is white．It's from my uncle Sam．He works in New York and comes back to London every December．I like mv smart phone．It is useful.
    The school rules don't allow(允许)us to take smart phones to school,so I usually use it after school or on the weekend．When I go out with my friends，I like keeping it in my bag．So my family can call me at any time．When I don't go to school．I like to call my friends to talk to them，or ask them for help with my study．I'm not very good at math，so I put an APP(应用软件)about math in my smart phone to help me． It is fun and helpful．I also use the smart phone to do some reading，play games，and watch movies．Isn't it great?
    Sometimes smart phones are not good for people．Some people spend too much time on it．I like my smart phone and I know how to let it help me. It's my good friend．
根据材料内容选择最佳答案。

1883年《申报》记载:“上海为通商大埠，西人之处此者最多，华人类多效其所为……至于坐马车、登轮舟，华人亦皆以为乐，甚至雪茄之烟衔于口中，弹子之房游于暇日，大餐之馆座客常满，左手持叉右手执刀，以恣大嚼者，皆华人也。……酒则香饼（槟）、茶则加非（咖啡），日用之物皆以一洋字者为佳。”这反映出（   ）

．已知奇函数在上单调递减，且，则不等式＞0的解集是（ ）

的相反数是（   ）．