题目

完形填空：阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项。Dear Aihua, How are you? I've been busy arranging my 1 with my brother, Colin. We plan to 2 a few weeks travelling before he is admitted to the univers ity. We will 3 so many exciting places and do lots of 4 things. My first 5 is Morocco, in northern Africa. We're going to 6 camels through the Sahara Desert. I 7 it will be very hot, dry and 8 there. Even though it may feel uncomfortable to sit on a 9 for almost a week, I still look forward to it. Then12．设集合A={4，a，b}，B={a，a2，-2a+2b}，且A=B，求实数a，b的值．