情态动词和虚拟语气

e.g. 1) If you had followed the doctor’s advice, you would be quite all right now.(从句指过去,主句指现 在)
2) If I had spoken to him yesterday, I should know what to do now.
定等，例如： 1）He shall get what he wants. 2）You shall not leave your post this afternoon.
2、情态动词的推测性用法 1）肯定句 must; could; may; might（把握性依次降低） 2）疑问句 can/could 3）否定句 can’t/couldn’t; may not; might not（把握性依次降低）
to; may; might will/would
would表示过去意愿
will
used to/would
used to常含有过去曾经，现在不再的含义; would 则 表示过去某一环境下倾向性的习惯
can may/might; can/could
请求允许时用过去式表示“委婉”“
must；have to should; ought to
主 It is 上述动词的过去分词 语 从 句
that主语+ (should) do/be done ...
表 ...上述动词的同源名词 语 （如suggestion, order, 从 proposal, plan, idea, 句 command, request等：）
is/was
同 位 ...上述动词的同源名词 语 （如suggestion, order, proposal, 从 plan, idea, command, request等：）
功能 能力 可能性 意愿 现在习惯 过去习惯 客观可能/潜在的可能性 允许；请求许可 必须；一定 应该
需要
敢
禁止
情态动词 can/could; be able to
用法说明 was/were able to do sth.表示过去成功做了某事
will/shall; can; should/ought 可能性依次变小
二）虚拟愿望句
1、wish
主句
主语 + wish
从句
（同时） (that) 主语 过去式（be 用were） （先时） (that) 主语 + had + 过去分词 （后时）(that) 主语 + would/could +动词原形
e.g. I wish everyone were active in class. I wish I had done better in the mid-term exam. I wish (that) you would get a good job.
注：as if /though 表示“有可能实现的事实”时，从句用陈 述语气。
e.g. It is so cloudy. It looks as if it is going to rain.
四）其他的虚拟语气
It is/was+ adj./n.如： important, necessary, natural, essential, vital strange, (a pity/a shame, no wonder, ) desirable, surprising, unbelievable, incredible
句
that主语+ (should) do/be done ... that主语+ (should) do/be done ...
四）as if / though引导的状语从句
主 as if （同时） 主语 +过去式（be 用were）
句
（先时） 主语 + had + 过去分词
（后时）主语 + would/could +动词原形
3、 would rather
主语 would rather （现在或将来） (that) 主语 过去式（be 用were） （过去） (that) 主语 + had + 过去分词
e.g. I’d rather you posted the letter right now. My wife would rather I had not bought the red curtain. She is not happy with this color.
应该注意的特殊问题二
从句省略if , 用倒装句式“were,had,should+主语...” e.g. 1)Were I in school again, I would work harder.
2)Had you been here earlier, you would have seen him. 3)Should there be a meeting tomorrow, I would come.
2、 if only If only
（对现在愿望） (that) 主语 过去式（be 用were） （对过去的愿望） (that) 主语 + had + 过去分词 （对将来的愿望）(that) 主语 + would/could +动词原形
e.g. If only I had taken his advice! (it would have been better)我要是听 他的话就好了! If only I had wings!
must表示说话人主观要求；have to 表示客观上“不 得不”
表示“应该”“可能性”两者可以互相替换；should 还能表示“万一”“竟然”的意思
need dare mustn’t
用 于 否 定 和 疑 问 句 。 否 定 式 needn’t do 或 don’t /doesn’t need to do或don’t have to do; 疑问式Need + S+ do...?或Do/Does+ S + need to do...?
主语 + (should)+do/be done/have done
e.g. It’s surprising that she should look so miserable.
It is (about/ high )time
( that ) 主语 + 动词过去式（be多用were） 或should(不能省) +动词原形
应该注意的特殊问题三
含蓄条件句：虚拟条件暗含在介词短语或上下文中，从句不表 现出来。 e.g. I could never go to college without his help. (= If there were not his help, I could never go to college ) But for (要不是)your help, we should have failed.(= If you had not helped us, we should have failed.) I was ill that day. Otherwise I would have come. (= If I hadn’t been ill that day, I would have come.) I would have visited you last week, but I was so busy. (= If I had not been so busy, …
二、虚拟语气 一）虚拟语气在条件句中的应用
与现在事实相反 与过去事实相反 将来不可能实现
从句谓语
主句谓语
动词过去式（be动词一 律用were)
had+过去分词
would /should/could/ might +动词 原形
would/should/could/ might + have + 过去分词
e.g. It’s time that you should go/went to school.
﹣E﹣ ND
注意：对现在情况推测时，情态动词后跟动词原形，多为be; 推测现在正 在做的事情时，情态动词后跟动词的进行时(be doing); 对过去（现在以前） 发生的事情进行推测时情态动词后跟完成式（have done）
其他和完成式连用的情态动词
1、 should (not) have done; ought (not) to have done表示本来应该做实际未做或本来不该做实际 做了 2、need (not) have done 表示本来有必要实际未 做或本来不必实际做了 3、could have done表示本来可以实际未做 4、might have done表示本来有可能实际未发生
情态动词和虚拟语气
学习目标 1、了解情态动词的概念 2、掌握情态动词的基本用法 3、了解并正确使用常见的虚拟语气
一、情态动词
情态动词的概念 情态动词虽有自己的词汇意义，但不能单 独作谓语，要和动词原形、动词的完成式 （have done）或进行式（be doing）连用 构成句子的谓语。
情态动词的功能和用法
用 于 否 定 和 疑 问 句 。 否 定 式 daren’t do 或 don’t/doesn't dare (to) do疑问式Dare+ S + do...?或
Do/Does+ S + dare (to) do...?
情态动词的其他用法
1、shall的其他用法 1）用于一、三人称的疑问句，征求听话人意见，如： Shall he attend the meeting? Shall I fetch a doctor for you? 2）用于二、三人称的陈述句表示命令、恐吓、威胁、许诺、警告、规
1）动词的过去式 2） should +动词原形 3）were to+动词原形
would/should/could/ might + 动词 原形
应该注意的特殊问题一
错综时间条件句：当条件状语从句的行为和主句表 示的行为所发生的时间不一致时，动词的形式要根 据它所表示的时间来调整。(混合时间条件句)
三）表示主张、建议、命令、要求的虚拟语气
主句
从句
宾 主语+ insist
(that) 主语+ (shouldmand/instruct
从
suggest/advise/propose/recommend
句
ask/request/require/demand