定义在R上的函数f（x）满足

①对任意x，y∈R有f（x+y）=f（x）+f（y）

②当x＞0时，f（x）＜0，f（1）=-2

（1）求f（0）值；

（2）判断函数f（x）奇偶性；

（3）判断函数f（x）的单调性；

（4）解不等式f（x²-2x）-f（x）≥-8．

短文改错（共10小题；每小题1分，满分10分）

Dear Tom,

I know there have trouble for you to communicate with others, and you may often feel lonely．That's why you are new from here and people don't know about you．But I think you can make it if you can follow the advices below．

First, you should take a active part in the discussions and show your own opinions about the matters．At the same time, never fail to listening to other people's views．Second, you should learn your classmates' likes and dislikes．Only in this way can you be able to get to know more different people and show them that you are actually very friendly．Last but not least, I will always be ready to help you．We can take part in some activities together, that I can introduce you to others．

As time going on, people will know you better and be willing to make friends with you．

Best regards．

Peter