考研英语--谓语动词（7）
动词是表示动作或状态的词，有时态、语态、语气、数的语法范畴。
一、动词的分类和变形
从不同角度划分，动词可以分为: 及物 vs. 不及物; 实意动词 vs. 助动词; 系动 词;
限定动词 vs. 非限定动词;谓语动词 vs. 非谓语动词。
a 助动词
助动词无实际意义;不单独做谓语;帮助构成时态、语态、语气、否定、疑问;后 面的实意动词为非限定形式(不再受主语的控制)。
表示时态的助动词:be, have, shall, will
表示语态的助动词:be
表示语气的助动词:should, would,
b 情态助动词:
can (could), may (might), must, need, ought to, dare (dared), shall (should), have to...情态助动词只有情态含义，表明说话人对动作的观点，
例如 需要、可能、意愿、 怀疑等。不单独作谓语，后接动词原形。(情态动词有不少特殊考点)
大部分无人称变化，只有少部分，can, will, have to, be to 有过去式;
只有 have to do 有三单和将来时;
大部分有多个含义，如 can, may 等;
把下列句子变为否定、疑问:
I loved you.
I have finished the homework.
The theater is far away from here.
I can remember every word he said.
二. 动词的形态
动词有原形、第三人称单数、过去式、过去分词、现在分词五种形式。其中，大部分过去式和过去分词形式相同。
a 动词三单:
一般加 s:works, seems, follows;
以 s, sh, ch, x, z 等结尾的词加 es: pass, push, buzz, mix, catch; 辅音加 y 结尾，变为 ies:carry, try
b 动词过去式:(不规则变化详见附录)
一般加 ed:help, stay, want
以不发音的 e 结尾，加 d:hope, like
重读闭音节，双写加 ed:shop, plan, clap, refer, admit
c 动词的 ing:
一般加 ing:going, doing
以不发音的 e 结尾，去 e 加 ing:time, realize, make
重读闭音节结尾，双写加 ing:sit, begin, run
三、动词的语法范畴
a . 语态
汉语多主动，英文多被动。英文被动由 be (get) + done 构成。
主动变被动:o——s;v——be done;by + 原主语
The manager signed the papers. — The papers were signed by the manager.
有时 by 不表示动作发出者，而是表示原因、方式:
A tree is known by its fruit.He is paid by the day.
b. 语气
英文语气有陈述、疑问、感叹、虚拟等。但是考查的重点难点仅在于虚拟语气。
虚拟语气用在谈及非真实事件，表明愿望、命令、建议等情况下。
原形虚:主句表示建议、命令、要求等，从句为 sb. (should) do sth.
I insist that you (should) take the money.
My suggestion is that we (should) keep an eye on him.
过去虚: 状语从句中，时态比真实时间向前推一格
If I were you, I wouldn’t do that.
If I were to do it, I would do it in a different way.
If I had studied harder, I would have passed.
倒装虚: 部分倒装(助动词提前)可表示虚拟，少数情况可以完全倒装
Were I you, I wouldn’t do that.
Were I to do it, I would do it in a different way.
Had I studied harder, I would have passed.
含蓄条件虚:状语从句中，时态比真实时间向前推一格
Without you, I would not have achieved anything.