If条件句和虚拟语气

精品文档 1欢迎下载 If 条件句和虚拟语气 ifif 条件句和虚拟语气条件句和虚拟语气 包含条件从句的句子叫条件句 条件句有两类 一类是真实条件句 First conditional 一类是非真实条件句 Second Conditional 如果假设的情况是有可能发 生的 就是真实条件句 如果是纯属假设情况或是不可能发生或可能性不大的情况 则是 非真实条件句 1 真实条件句 可用 if 和 unless 引导 1 一个动作发生 另一动作随之发生 I ll lend Peter the money if he needs it If he has time he will come If he doesn t come before 12 o clock we won t wait for him I shall go tomorrow unless it rains I won t go to her party unless I am invited 2 表示命令 建议或请求 这时的 if 等于 when If she telephones let me know Give my love to Lawrence if you see him 3 will 用于 if 从句中 不表示将来 而表示愿意或坚持的意思 If you will come this way I ll take you to the manager s office If you will get drunk every night it s not surprising you feel ill 2 非真实条件句 精品文档 2欢迎下载 非真实条件句包括虚拟条件句和错综时间条件句 1 虚拟条件句分三类 其结构列表如下 条件从句结果主句 与现在事 实相反 If 主语 动词的一般过去 时 be 动词一般用 were 主语 would could might 动词原 形 与过去事 实相反 If 主语 had 过去分词主语 would could might have 过去分词 与将来事 实相反 If 主语 一般过去时 If 主语 were to If 主语 should 动词原 形 主语 would should could might 动词原形 If I become president I ll make all of my people live a happy life 竞 选总统的候选人这样说 If I became president I d make all of my people live a happy life 一个 小学生这样说 l 以下与现在事实相反 He wouldn t feel so cold if he were indoors I am sorry I am very busy just now If I hade time I would certainly go to the movie with you l 以下与过去事实相反 If you had come here a little earlier you would have met the pop star I don t know what would have happened if Jane hadn t been able to speak Japanese l 以下推测将来 If I were to do the work I should do it in a different way If it should rain again what else could we do 精品文档 3欢迎下载 2 错综时间条件句 在错综时间条件句中 虚拟条件句和主句动作发生的时间不一致 因此 主句和从句 的谓语动词要根据各自所指的不同时间选用适当的虚拟语气形式 If you had spoken to him last time you saw him you would know what to do now 过去 现在 If I were you I wouldn t have missed the film last night 现在 过去 条件句可分为真实条件句和非真实条件句 真实条件句表示句子所描述的事件是事实 或在说话人看来可能实现的事情 非真实条件句表示的条件与事实相反或不大可能实现的事情 即我们所说的虚拟语气 引导真实条件状语从句的连词 和词组有 if unless once as so long as so as far as in case provided that providing that suppose that supposing that given that assuming that on condition that 等 虚拟语气的使用范围及判断 一 虚拟语气表示一种不能实现的假设 该语法主要用于 if 条件状语从句 也可用于主语从句 表语从句 宾语从句等 二 if 条件状语从句中虚拟语气的判断 判断是真实条件句还是 非真实条件句 只有在非真实条件句中才使用虚拟语气 通过句子意思 看假设的条件是 否能够实现 能够实现是真实条件句 不能使用虚拟语气 假设的条件不能实现则是非真 实条件句 要用虚拟语气 判断这个假设是与哪个事实相反 通常有三种情况 与过去 事实相反 与现在事实相反 与将来事实可能相反 三 后退一步法 后退一步 法是指在准确地判断了该句与哪一事实相反后 按虚拟语气的后退一步法处理从句谓语动 词的时态 即 在非真实条件状语从句中 谓语动词按正常情况 后退一步 也就是 与过去事实相反 在从句中用过去完成时形式表示 与现在事实相反 在从句中用过 去一般时形式表示 与将来事实可能相反 在从句中用过去将来时形式表示 主句中 则用情态动词 would should could 等加一个与从句一致的动词形式 例 If I had come her yesterday I would have seen him If I were a teacher I would be strict with my students If it should snow tomorrow they couldn t go out 四 注意事项 if 条件句中如有 were should h