Since/before/it is+adj/n+doingthere be固定句型 It is + 一段一段时间 + since从句从句关于这个句型要注意以下几个方面(时态搭配和辨别v.是延续性v.还是短暂性v.) 1.it is/has been +时间段+ since sb. have done(该v.必须为延续性v.,翻译时直译) •eg. It is 5 years since I have lived here.(live为延续性v.故直译为：自从我住在这儿已经5年了)2. it is/has been +时间段n.+ since sb. did(如v.为短暂性v./瞬间性v. 翻译时直译,如为延续性v./表示状态词 翻译时反译)It is 5 years since I lived here.（live为延续性v.故反译为我已经5年不住这儿了 It is 3 years since I smoked.（smoke为延续性v.故反译为我已经3年不吸烟了 I haven’t heard from him since he lived in London.I haven’t heard from him since he has lived in London.Since 从句中的谓语动词是延续性动词或状态动词，过去时态表示动作或状态的结束，现在完成时表示动作或状态的开始并延续至今：(他已不在London，从他离开London之时起到现在我就没有收到过他的来信)(他还在London,从他搬到London起到现在我就没有收到过他的来信) 1) It is / has been ten years since he left Beijing. 自从他离开北京已经十年了。
2) It is / has been ten years since he was a doctor. 他不当医生已经十年了3) it’s three years since I smoked.我不吸烟有3年了4) it’s three years since I began to smoke.我抽烟有三年了5）It is 3 days since the accident happened.（happen为短暂性v.故直译为：自从这场车祸发生已经有3天了 • 1）在 “It was + 一段时间 + before从句句型中，若主句是一般过去式，从句也是一般过去式时： ① 若主句是肯定句，翻译成“过了多长时间之后才……”例：It was long before they found their son.过了很久他们才找到他们的儿子② 若主句是否定形式，翻译成“没过多久就……”例：It was not long before the couple met again.没过多久这对夫妻就见面了 •2)在“It will be + 一段时间 + before从句”句型中，若主句是一般将来时，从句也是一般现在时：①若主句是肯定句，翻译成“要过多长时间之后才……”例： It will be half a year before I come back.半年后，我才回来。
② 若主句是否定形式，翻译成“用不了多久就……”例： It won’t be long before we meet again.我们不久就会见面 It is+名词短语名词短语.+ doingIt is + no use, no good (fun, a great pleasure, a waste of time, a bore...)等名词等名词+doing sth.It is no good objecting.反对也没有用反对也没有用It is a great fun playing football．打篮球很有趣．打篮球很有趣It is a waste of time trying to explain．．It is+adj+doingIt is + useless (nice, good，，interesting, expensive等形容等形容词词)+ doing sth．．It is useless speaking.光说没用光说没用It is nice seeing you again．真高兴又遇到了你．真高兴又遇到了你 1. There is no doing 结构。
其意为“不可能…”、“无法…”：There’s no denying the fact. 这一事实不容否认There is no getting over the difficulty. 这困难无法克服2. There is no difficulty in doing sth. 结构意为“做某事没有困难”：There is no difficulty in finding his office. 找到了他的办公室没费一点劲There was no difficulty in carrying out the plan. there be结构的九个惯用句型结构的九个惯用句型 3. There’s no doubt… 结构意为“毫无疑问…”： There is no doubt of his success. 4. There is no hurry (to do sth) 句式其意为“不用急(于做某事)”：There’s no hurry to return the book. 5.There’s no need for…结构其意为“不需要或不必要…”： There is no need for help. 不需要帮助。
There is no need for you to go. 你没有必要去 8. There is no sense in doing sth 结构意为“做某事没有道理或好处”：•There’s no sense in criticizing him. 批评他也没有用9. There’s no point in doing sth 句式意为“做某事没有用”：•There’s no point (in) telling her about is. 告诉她没有用 It was+一段时间+since从句•It was+一段时间+since从句 从句用had done）,主句用一般过去式.•It had been+一段时间since 从句（did），主句had done•It was three years since Jack had been a teacher. •It had been three years since Jack was a teacher.•杰克不当老师已有3年了 。