两人对话，乙方对甲方的问话常可用简短回答作出 反应。例如： Do you like it? -- Yes，I do.这同样适用于陈述句的场合： You worry too much．-- No，I don't.在后一种情况下，乙方也能"So＋do＋主语"之类 的结构表示看法。
　　例如甲方说"我喜欢苹果"，乙方 如果想表示"我也喜欢苹果"，英语可以说：
　　A：I like apples.
　　B：So do I．（＝ I like apples，too。）
　　这里的so在意义上相当于in the same way，即同样、 也那样，作简短反应表示同样看法时常用之。
就诸如此类的四种结构略作介绍。
　　1．"So＋do＋主语"结构 在简短反应中表示"我也如此"或"另外一个人也 如此"时，也就是主语不同于上文的主语以及上 文并无可用于构成倒装的动词（即操作词时）， 可用此结构。例如： A：I like playing football. B：So do I./So does my brother./So did my father. 如果上文有可用于构成倒装的动词时，则用相同 的动词或根据不同人称用同类的动词。 I must go -- So must I. John can speak French．--So can I. I've got a new car．--So has John. She is clever.-- So is he.
　　2．"Neither/Nor ＋ do ＋ 主语" 结构 如果上文表示否定意义而在简短反应中表示同样 看法时，可用此结构。例如，甲方说I can't swim， 乙方如果想表示"我也不会游泳"，英语可以说 Neither can I. / Nor can I（＝I can't either）。
　　又例如： A：He doesn't speak French. B：Neither/Nor do I. Neither/Nor does my brother. Neither/Nor does my father. 关于以上两种结构，有两点说明：
　　第一，能用动词缩略形式。例如： I'm going to London. ---So's John。(is) I've been to New York. ---So's John.(has) I'd have gone to Tokyo if I could．---So'd John.(would) John hasn't got a visa. ---Nor've do I．(have) Jim and Mary aren't acting in the college play. ---Neither's Peter.(is)
　　第二，上述甲乙对话如用and连成一句可出自一人 之口。例如： John can speak French and so can't I. John can't speak French and neither/ nor can I. John speaks French and so do I. John doesn't speak French and neither/nor do I. 上述斜体部分相当于and I can, too / and I can't either / and I do too / and I don't either 的意思。 　
　　3．"So＋主语＋do"结构 在简短反应中，对别人所说的情况加以肯定以及 主语与上文主语相同时，可用此结构，注意，这 里不用倒装同序；so 的意义相当于indeed, certainly，即"不错"、"对了"。例如： A：John smokes a lot. B: So he does．(=He smokes a lot indeed.) 这类简短反应往往带有说话人的惊奇口吻。例如： A：Look，it's raining! B: So it is. 在这里，So it is的含义是 You are right! It is raining；and this surprises me. 　
　　4．"Nor＋主语十do"结构
　　如果乙方想对甲方所否定的情况加以肯定时，可用此 结构(注：在这类结构中，neither少见)例如： Look! It isn't raining any more!
　　---Nor it is!
　　This cup hasn't got a handle!
　　---Nor it has!
　　四种结构的介绍就到此为止。下面从L.A. Hill所着 An Intermediate Refresher course 一书摘引一则 对话供初学者观察上述四种结构在上下文中的使用 情况。
　　Derothy: Look it's raining!
　　Donald: So it is! I'm not going out this afternoon now.
　　Dorothy：Nor am I. You and I haven't got anything to do this evening, you know.
　　Donald: Nor we have! We can go to the cinema then.
　　Derothy: So we can.
　　Donald: There's a good film on at the "Metropole".
　　Derothy: So there is! Shall we go?
　　Denald: Yes, let's.
　　Derothy: But it doesn't start until 6 o'clock.
　　Denald: Nor it does! I thought there was an early performance too.
　　Dorothy：So did I . Well, I don't want to sit about doing nothing until 6.
　　Donald: Nor do I …Oh, look, it isn't raining any more.
　　Dorothy: Nor it is! I'd like to go for a walk.
　　Donald: So would I…OH, who's that coming up the road?
　　Dorothy: It's the postman.
　　Donald: So it is! He's very early. The evening newspaper hasn't even arrived yet.
　　Dorothy: Nor it has! That's late today. I hope the postman has a letter for us.
　　Donald: So do I - but I don't want any more bills!
　　Dorothy: Nor do I!
　　Donald: Here he is…there's a parcel for us!
　　Dorothy: So there is! I wonder who sent it.
　　Donald: So do I. I wasn't expecting a parcel.
　　Dorothy: Nor was I. Oh, it's from Mother - they are woolen clothes for the baby!
　　Donald: So they are! She must have knitted them herself!
　　Dorothy: There's no letter in the parcel.
　　Donald: Nor there is! I find that strange.
　　Dorothy: So do I. She always writes to us on Sundays. Oh, well, perhaps we shall get a letter from her tomorrow.