an=3的n次方+2的n次方+（2n-1）求前n项和

He has got three ______ A.pair of trainers B pairs of trainer C pairs of trainers D pairs trainers应该选什么? I’ve got two pairs of Chinese chopsticks.对划线部分提问.划线部分为：two pairs of day,what,your,birthday,year,this,is?连词成句 season in what your is birthday连词成句还有一个：the honey are the ants eating what is your______ birthday?He is 12 years old.He is ___ ___ boy.I often help my mother with housework .I often __ my mother ____ ____.改为同义句 What date is your birthday?用英语怎么回答?我是1993年,4月12日的. what is the best way to get knowledge?中的 What is the best way to ____ English well?Listen to good English first._____use English at every chance.We have some chances to _____it around us. Most of the people know it译成：大多数人知道这个.我想问为什么people不用加s? 求下面两个的一般过去式,现在进行时；一般将来时（两个）The firemen is puting out the fire.Weare cleaning our classroom. three,wants,buy,he,of,trousers,pairs,to连词成句 (A) Fill with the proper forms 用括号内所给单词的适当形式填空\x0521.Peter wants to be a good doctor for ____________(child) in the future.\x0522.We often do ____________(listen) in the new language lab.\x0523.____________(do) Tom watch The cook has three ( ) blue trousers. A.pairs B.pairs of C.pair of 为什么a box of chocolates 后面要加s? He wants to buy two pairs of glasses.翻译 he wants to buy three packest of cigarettes has,borther,jim's,pairs,three,earphones,of,连词成句 take your ill brother to the hospital at once 改错 He gets to school by bike.(改为同义句） He _____ ____ _____ ______school If only ,I only if hope if hope if only if/if He also (has) two pairs of (pants).He also (has) two pairs of (pants）.这样填对吗? What is the best way to get a seat on a bus?英语脑筋急转弯有人说加个h,那么bush和这个八竿子打不着啊 (脑筋急转弯) 在公交车上抢座位 最好的方法 What is the best way to get a seat on a bus? what is the best way to get a seat on a hus Father_____a bike for me as my birthday present.A.was oppered B.is oppered C.oppered to buy D.oppered to buying My birthday is coming.My uncle gave me a new watch ____ a present yesterday My father bought me a new iPad for my birthday.You are a lucky （ ）A,guy B,cat C,people D,son『我认为是在A或D里面选,有dog就好了……选的什么呢?』 You are the angle in my