题目

若a2-b2>0,试化简a-b. 答案：解:原式=a-b=-, 因为a2-b2>0, 所以a+b>0且a-b>0或a+b<0且a-b<0. 当a+b>0且a-b>0时,原式===. 当a+b<0且a-b<0时, 原式==.第三节：书面表达(满分25分)假设你是李华，你收到你的英国笔友Bob的一封E-mail（见图一），请根据邮件内容和你所获得的海报（见图二）提供的信息，给Bob回一封邮件。Dear Li Hua，How are you going on recently? I’m so glad to tell you that I have planned to go to Beijing to study Chinese in my coming holiday. Would you please help me to find a Chinese training school, and give me some information about it? Write back soon.                                            Bob(图一）LET’S TALK IN CHINESECourse: Chinese for beginners         Time: January 20--- February 19Place: No.1 Lecture Hall             For more information:www.redstar.org.Red Star language School            Tuition(学费)：2，000 RMB(图二）注意：1.词数120左右              2.根据内容要点适当增加细节，以使行文连贯。Dear Bob，