等差数列前n项和Sn/Tn求等差数列an/bn

就括号部分提问：We have(Chinese,maths,English and so no)to day 英语句子里在什么情况下and变or? 什么时候英语句子中用or,什么时候用and 请问英语句子里面,...or...and...应该怎么理解?比如：you need bachlor degree in information system OR bachlor degree in Electrical Technology AND three years of relevant working experience. if 与 and, or英语上的句子替换谁能举个例子,上初中,不要太难的,谢谢各位了. 英语中的否定句要不要把and改成or比如说I have a sister and a brother.改否定句I don’t have a sister or a brother.还是直接在I后加don't 就好？我好像记得老师有说过要但又一些练习的答案却没改到底是哪 以who为开头的句子,如果回答是'我,那用英语怎么说?应该是me 还是I .如果是I,那为什么说”me ,too"如果是me,为什么不用I 英语补全句子：我给我的朋友打电话让他来接我.I（ ）and ( ). 我的朋友和我!这句话翻译成英语!您看看哪句是对的!1.My friend and My friend and me!哪句是对的! I Lomo You and You Lomo Me 我英语不好,谁会这句的?（用文字带上,差I Lomo You and You Lomo Me 我英语不好,谁会这句的?（用文字带上,差不多跟念英文的一样） 请帮我讲解一下这个英语句子：Anything less than a B from me and I'm in trouble.上文是：My parents expect me to do well in school,even though my brothers are pretty bad students.请详细讲述一下该句型的用法, 英语句子中,and前,为什么加",例如：For one thing it costs too much,and for another thing. 完成句子 英语〈接第五题--and______〉 英语and在这句话中是词,为什么?The pay phone is between the post office and the library. then可以和and一样连接两个句子吗,and与then的区别?then的用法? and和then表然后的区别 英语then的多种用法 only then"用法要具体的用法和例句! then 在英语里面怎么哥用法? if then 在英语中可以出现在同一个句子吗例如if you make a mistake,then you will be punished.还是说if you make a mistake,you will be punished.因为有的关联词,比如说althouth he is young,but he lacks energy.这种就只能用a 英语中 if和then是不能同时使用?请指教 if then语句的问题ASP文件中需要写一个if then语句大概就是if "leixing"=A1then[展位预定]end if可是我不会按照格式来编写,一楼的出现错误二楼的leixing=任意都显示三楼的leixing=任意都不显示 Life is a bitch and then you die.谁可以翻译一下这句英语啊 and he is kind to his students then 英语翻译 谁翻译一下这句英文.and then have u knew that god is a bitch so would u mean? 这句英语里的then是啥意思?一哥们儿（老外）过来跟我说：We will have a soccer match tomorrow then.我知道他意思是明天要去踢球,但是那个then是什么意思?是不是"回头"的意思? Brokenhearted then free这句用英语翻译过来时什么意思? 英语翻译So that was the year premier,great,but eh,newspaper from back then weren’t online,so,how do I do?这句话怎么翻译呀,大师! finish then start这句英语是什么意思? Cry once more then I will surrender 帮忙改这句英文 我觉得太多and了,还有最后一句的of 改为for好吗?But he has made the issue well resolved by being as interpreter for the photo consultant from Australia and Chinese and foreign journalists of both side,as well as th 英语好多错的,怎么改