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    Some people learn a foreign language easily. Others may not. How can you help yourself learn English? I think there are two ways to make learning English a little easier and more interesting.

    First, you should build up confidence（自信）. If you believe that you can learn, you will learn. When you read or listen to something, you may not be able to understand（理解） it all. Don't worry. You can use a dictionary to help you. You can ask your teacher or friends to help you. Do not be afraid of making mistakes. You can learn from mistakes.

    Second, practise using English. For example, write a diary in English every day, and you'll be able to write better. Speak English whenever you can. You may practise with your friends after class. Then you'll be able to speak better.

    Remember the famous saying, "Practice makes perfect." The more you practise using English, the better you'll learn it.

已知函数f（x）=x﹣$\frac{1}{x}$，求证：

（Ⅰ）f（x）是奇函数；

（Ⅱ）f（x）在（﹣∞，0）上是增函数．