在同纬度的地区，相对位置偏东的地区，与偏西的地区相比（　　）

网络信息的开放性对于自控能力不强、极富好奇心的青少年具有极大的诱惑力，网络中的黄、赌、毒、暴力等信息严重损害了青少年的身心健康。为此，下列对青少年建议正确的是（    ）

①要树立正确的是非善恶观

②要提高自控力，拒绝不良诱惑

③关停非法经营网吧

④要提高辨别是非的能力，拒绝上网

已知梯形的面积公式为S=$\frac{(a+b)h}{2}$

（Ⅰ）求函数f（x）的解析式；

（Ⅱ）判断函数f（x）在区间（0，+∞）上的单调性，并用单调性的定义证明．

    Jiaozi is the Chinese name of dumplings. We have all kinds of dumplings with meat or vegetables in it. Jiaozi is very delicious and it is very popular (受人喜爱的) in China, especially (尤其) during Spring Festival. People usually eat jiaozi on the eve of Spring Festival. Why do people like eating jiaozi? Because Spring Festival is Chinese New Year. People eat round jiaozi to show their wishes for good luck. The history of jiaozi is about 2, 000 years. Eating jiaozi is a very happy thing. When all the families make jiaozi together, you'll feel very happy.