题目

点A（?1，2）关于原点对称点B的坐标是 ．  答案：【答案】（1，?2）．【解析】试题分析：根据关于原点对称的点的坐标特点：它们的坐标符号相反,可直接得到点A（?1，2）关于原点对称点B的坐标是（1，?2）．请修改下面的短文。短文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。增加：在缺词处加一个漏字符号(∧)，并在其下面写出该加的词。删除：把多余的词用斜线(\)划掉。修改：在错的词下画一横线，并在该词下面写上修改后的词。注意：1.每句不超过两个错误；2.每处错误及其修改均仅限一词；3.只允许修改10处，多者(从第11处起)不计分。Dear Tom,I haven’t heard from you for a long time. What is everything going with you? To be honest, I amnot used the food here and the weather always makes me uncomfortably. Therefore, I find that difficult to concentrate on my studies. The new teachers are friendly and they speak so fast that I can’t quite understand them. This often discourages from me in class. What’s bad, I always feel lonely after school. I really want to go back to my previous school, studied together with you.I was very worried, Can you give me some advices? I'm looking forward to your reply.Yours sincerely, Jack