语法要点
易错语法点，配例句讲清什么时候用哪个。
共 24 条
共 24 条
主谓一致：就近原则Either you or he is right. —— 由 either...or、neither...nor、not only...but also 连接的主语，谓语与**最近的那个**保持一致。上例离动词最近的是 he，所以用 is。语法要点现在完成时 vs 一般过去时I have lived here for 5 years. / I lived there in 2010. —— 现在完成时强调「与现在有关」，常配 for / since / already / yet / ever；一般过去时强调「过去某个时间点结束」，必须配明确过去时间（in 2010、yesterday）。两者不能和具体过去时间连用完成时。语法要点定语从句：that 与 whichThe book that/which I bought is good. —— 限制性定语从句中 that 和 which 多数可换；但先行词被 all、only、序数词、最高级修饰，或先行词为不定代词时，通常只用 that。介词提前时只能用 which（in which）。语法要点虚拟语气：if 条件句If I were you, I would take it. —— 与现在事实相反：if + 过去式（be 用 were），主句 would + 动词原形。与过去相反：if + had done，主句 would have done。与将来相反：if + were to do / should do。语法要点非谓语：doing 与 to doI enjoy reading. / I want to go. —— enjoy、finish、avoid、mind、practise、suggest 等后接 doing；want、hope、decide、plan、agree、refuse 等后接 to do。remember / forget / stop 接两者意思不同：remember doing（记得做过）/ remember to do（记得去做）。语法要点倒装：否定词提前Never have I seen such a thing. —— 否定副词置于句首（never、hardly、seldom、not only、no sooner）时，主句要用部分倒装：把助动词提到主语前。no sooner...than 与 hardly...when 是固定搭配。语法要点比较级：as ... as 与 thanHe is as tall as I am. / He is taller than I am. —— as...as 中间用原级，否定可用 not so...as；比较级用在 than 前。比较对象要对等：不能说 His English is better than me，应为 better than mine。语法要点情态动词表推测It must be true. / It can't be true. —— must 表肯定推测（一定），can't 表否定推测（不可能），may / might / could 表可能。对过去的推测用 must have done / can't have done。注意 mustn't 表「禁止」而不是「不可能」。语法要点被动语态的基本结构The letter was written by Tom. —— be + 过去分词，时态体现在 be 上。带双宾语的动词可有两种被动（He was given a book / A book was given to him）。含情态动词时：must be done。语法要点there be 句型的时态There is / There was / There will be —— there be 的 be 随后面的名词单复数和时态变化。就近原则：There is a book and two pens.（离 be 最近的是单数，用 is）。语法要点a number of 与 the number ofA number of students are here. / The number of students is small. —— a number of = 许多（后接复数，谓语用复数）；the number of = ……的数量（谓语用单数）。这是高考与四六级高频考点。语法要点so ... that 与 such ... thatHe is so kind that everyone likes him. / He is such a kind man that everyone likes him. —— so 修饰形容词或副词；such 修饰名词短语。名词前有 many / much / few / little 时用 so（so many books）。语法要点it 作形式主语It is important to learn English. —— 真正的主语（不定式、动名词或从句）后置，用 it 占位。也可作形式宾语：I find it hard to concentrate。语法要点独立主格The work finished, we went home. —— 分词的逻辑主语与主句主语不一致时，自带一个主语，构成独立主格。表示时间、原因、条件或伴随，常见于书面语。语法要点only 引导状语置句首要倒装Only then did he realize the truth. —— only + 状语（then、in this way、after...）置于句首时，主句部分倒装。但 only 修饰主语时不倒装：Only he knows the answer。语法要点将来时的几种表达will / be going to / be about to / be to —— will 表单纯将来或临时决定；be going to 表计划或已有迹象；be about to 表马上；be to 表按安排或命令。语法要点引导词 whether 与 ifI wonder whether/if he will come. —— 宾语从句中两者常可换；但介词后、句首主语从句、与 or not 直接连用时只用 whether（whether or not）。语法要点分数的表达与主谓一致Two thirds of the students are here. —— 分子用基数词、分母用序数词，分子大于 1 时分母加 s（two thirds）。谓语由 of 后面的名词决定。语法要点used to / be used to / be used forI used to swim. / I am used to swimming. / It is used for cutting. —— used to do = 过去常常（现在不做了）；be used to doing = 习惯于；be used to do = 被用来做。三个结构意思完全不同，是高频易错点。语法要点强调句 It is ... that ...It was Tom that broke the window. —— 结构为 It is/was + 被强调部分 + that/who + 其余部分。判断方法：去掉 It is 和 that，句子仍完整，就是强调句；否则是定语从句。语法要点形容词作定语的位置a beautiful red Chinese silk dress —— 多个形容词并列修饰名词时，通常顺序为：限定词 → 评价 → 大小 → 形状 → 年龄 → 颜色 → 国籍 → 材料 → 用途 → 名词。语法要点关系副词 where / when / whythe house where I grew up —— 先行词是地点用 where、时间用 when、reason 用 why，它们在从句中作状语；若从句缺主语或宾语，则要用 which / that。语法要点must 与 have to 的区别I must go. / I have to go. —— must 偏主观（自己觉得必须），have to 偏客观（外部条件要求），否定形式意思差别很大：mustn't 是禁止，don't have to 是不必。语法要点现在分词的完成式 having doneHaving finished his work, he left. —— 强调分词动作发生在主句动作之前，常见于书面语。被动形式为 having been done。语法要点