圆x²+y²=4被直线l：kx﹣y﹣2k=0截得的劣弧所对的圆心角的大小为$\frac{\mathrm{\pi }}{3}$，则直线l倾斜角的大小为____ ．

     A good way to pass an exam is to work hard every day in a year. You may fail in an exam if you are lazy for most of the year and then work hard only a few days before the exam. If you want to be good at English, you have to read stories in English, and to speak English as much as possible. A few days before the exam you should go to bed early. Do not go to bed late at night. Before you start answering in the exam, read carefully over the question papers, and try to understand the meaning of each question. When you have finished your exam, read over your answers. Correct the mistakes and be sure that you don't miss anything out.