已知{An}是公差为d的等差数列,它的前n项和为Sn,S4=2S24,Bn=1An/An求d

Dear什么意思 我想考中级口译,听力里的听译好难哦,请高手出点训练的方法或建议吧, 怎么训练速记?有没有什么途径或好的方法,我现在正在准备中级口译的听力,听译那部分很麻烦!求方法! 动词不定式和现在分词有什么不同? 关于动名词,分词,不定式式的现在完成时.动名词,分词以及不定式式的现在完成时是不是只用于表示其动作发生在主句谓语动词之前?他们还有其他的作用吗? 我儿子 拼音总学不会怎么办? 孩子学拼音不会怎么办? please tell me something about American judicial system美国司法制度 who can tell me something about American superstitions? 上海中级口译听力有多少时间看题目?想知道听力有多少时间看题目,不看题目就听感觉一头雾水,有时间让你 不会一发试卷就听把...那就不太好了. Tom told me he[] much better than beforeA、is B、was C、be D、will Mike writes ______Tom.A:as careful as B:as good as C:much better than D:as careless as怎么我感觉都一样呃? please write b___and tell me something about you and China 中级口译 0607080910 真题 及听力 非谓语动词中,现在分词和动名词有什么区别?什么时候用having done? 分词是什么 分词是非谓语动词?为什么非谓语having+done having用ing形式 will you please go skating with me? -_____sure no.I don't yes,I'll no,I won't will you go shopping with me?是一般疑问句还是特殊疑问句? 中级口译有专门的训练软件吗? 以“珍藏的那一份记忆”为题,写一篇记叙文,500字 林肯当了几任的总统RT 很想为你唱首歌 作文关于感恩 急 初中英语课堂中教师提问的实践研究 怎么翻译成英语 作文 总想为你唱首歌 老师,初中英语课堂怎样导入比较好呢,还有有没有什么有效的让他们记单词的方式呢? Tom plays football______,if not batter than,Lester.选项为：A:as well B:as well as C:so well D:so well as Tom plays football ______ than I.A.more badly B.better John plays football as well as,if not better than, David.这句话怎么翻译?什么意思? Let’s go shopping（ ）和 Let us go shopping（ ）为什么一个用shall we,一个用will you...Let’s go shopping（ ）和 Let us go shopping（ ）为什么一个用shall we,一个用will you.要解析, let's go shopping作文 60字 提示 where are you going to buy who will go whth you what willlet's go shopping作文 60字 提示 where are you going to buy who will go whth you?what will you need to buy? —Will you go shopping now?—Not until I ____ my experiment.A．have finished B．will finish C．finished D．had finished选哪一个?为什么?请详解 , Tom‘s handwriting is_____ better than his elder brother’s A.more B.even C.very D.a few我认为这道题改选A啊,选A句子不是更通顺么?