1、If 条件句的用法 the usage of conditional,条件句,条件句（conditional）是由 条件状语分句（if 分句） + 主句 构成的复杂句(complex sentence)。 一共分为三种(3 types) 1 if whenever(the meaning is close to) 2 主将状从现 3虚拟,真实条件句,非真实条件句,The type 1 : ifwhenever,Type 1 是真实条件句（Real Conditional）的一种。在这种条件句中，if 的意义接近于whenever，所以这种句型又被称为“whenever-型”，可用于3种 场合：
2、 1、表示普遍真理和客观事实 （tell the truth) For example: If you pour oil on water, it floats. If the temperature drops to 0 degrees Centigrade, water freezes. 总结：由上两例可看出，凡表示不受时间限制的自然法则的条件句，其 if-分句和主句的谓语动词都用一般现在时 ： Pattern：（if) simple present +(Main) simple present,2、表示现在习惯动作 For example: If it rains, I go to wo
3、rk by bus. If I make a promise, I keep it . 总结：在上述表示现在习惯动作的条件句中， if-分句和主句的谓语动词也都是用一般现在时： Pattern： （if) simple present +(Main) simple present3、表示过去的习惯动作 For example: If I was hungry, I usually had a full meal. 总结：表示过去习惯动作的条件句中，If-分句和主句的谓语动词都用 一般过去时。 Pattern ：（if）simple past + （Main ) simple past.,The
4、 type 2 : 主将状从现,Type 2 是真实条件句的主体，最普遍最常用。（是重点） 一、基本形式：(2种） 1、if-分句用一般现在时表示将来时间，主句用shall / will / can / may (现在时） Pattern :（if）simple present + （Main）shall / will，etc 例句： If I see him again, I will tell him what you said. What will happen if they cant reach an agreement? If you set your alarm clock ,
5、you wont be late tomorrow.,2、if 分句 用一般现在时表示将来时间，主句用动词祈使式： Pattern : （If）simple present + （Main）imperative 例句： If you wake up before me, give me a call . If you go out this room, turn off the lights.二、变体形式（3种） 1、if-分句动词不管主语的人称和数如何，一律用should+不定式，主句动词可根据语义意图采用不同形式。 Example ： If it should rain again, th
6、e flowers will bloom. If you should come tomorrow, I would tell you the truth. 说明：在这里，should 仅表示一种不太肯定的婉转口气，并不影响条件的真实性。,2、在if-分句中用“will+不定式”并不单纯表示将来意义，这里的will是个表示“意愿”的情态助动词 = be willing to example : If you will reserve seats , we shall be sure of a comfortable journey.3、用 would 还是表示“意愿”，常用于 客气的请求，这时
7、，主语动词既可用will/shall +inf. 也可用would /should / could/ might +inf. Example : If you would try Italian food , you would like it.,注意： 省略了 to,willing to reserve,虚拟（第三条件句第四条件句）,这种是非真实条件句（unreal conditional) 的一种。所谓“非真实条件”，在语义上包含着不同程度的“非真实性”。这种类型的条件句也可分为基本形式和变体形式。,虚拟,基本类型 （if）simple past / were + (main) would
8、 (could ,might,etc) +inf 例如 If we caught the 10 oclock train, we would (could,might,ect)get there by lunch-time. 主句动词都用would could might ,etc 不定式。但可能性的程度不一样 If I knew how it worked, I could tell you what to do . (条件与现实相反，根本不可能告诉对方做什么）,虚拟,这种句型的动词形式还可根据语义意图采用进行体形式。If we were on holiday now , we d be h
9、aving a wonderful time,虚拟,变体形式(If) were to +inf+(main)would,etc+inf 例：If our train were to arrive punctually, we should have time to visit your sister. 要注意表示非真实条件的were to 与表示“义务”（obligation） 的am / is / are to 和was/ were to 的区别,虚拟,If he were to get in touch with me , I could explain.= Supposing he go
10、t in touch with me.(非真实条件）If he was to get in touch with me , why hasnt he done so ? = If the arrangement was that he should get in touch with me , why.? (表示“义务”） 里一个变体是在if-分句中用would + 不定式 表示不大可能实现的“意愿“ If you d cook the dinner , id do the washingup afterwards.（省略 to),虚拟,(If) had + -ed 分词 +Main woul
11、d (could might,ect) have -ed分词 例如 If we had caought the 10 oclock train ,we would have got there by lunch-time.We would /could /might have called you if we had known your telephone number,虚拟,如果句子的前半段 （if -分句） 是表现现在不大可能实现的条件，而后半段（主句）却表示与过去事实相反的情况，前后在逻辑意义上不相协调。但在保证句子合乎逻辑的前提下，也可根据语义意图混合实用俩种句型的动词形式If he
12、 had wanted to dance ,Id have taken him to discotheque(迪斯科舞厅）,虚拟,第四条件句的变体形式 （If）were to have + -ed 分词 +Main would (could, might, ect)have -ed 分词例如If you were to have asked me , I would have been only too willing to help.,虚拟,30分,20分,40 分,10 分,10分题,I used to walk to work.But if it _(rain), I went by b
13、us.rained,20分题,If you move to your left, you _(be)able to see the church,will be,30分题,He could repair the roof himself if he _(have) a long ladder.had,40分题,If the story hadnt been ture, the newspaper _(not print) it .wouldnt have printed,congratulations !,if i were a boy beyonce,If I were a boy Even
14、 just for a day Id roll outta bed in the morning And throw on what I wanted then go Drink beer with the guys And chase after girls Id kick it with who I wated And Id never get confronted for it. Cause theyd stick up for me.,If I were a boy I think I could understand How it feels to love a girl I swe
15、ar Id be a better man. Id listen to her Cause I know how it hurts When you lose the one you wanted Cause hes taken you for granted And everything you had got destroyed,If I were a boy I would turn off my phone Tell evveryone its broken So theyd think that I was sleepin alone Id put myself first And
16、make the rules as I go Cause I know that shed be faithful Waitin for me to come home (to come home),Its a little too late for you to come back Say its just a mistake Think Id forgive you like that If you thought I would wait for you You thought wrong,But youre just a boy You dont understand Yeah you dont understand How it feels to love a girl someday You wish you were a better man You dont listen to her You dont care how it hurts Until you lose the one you wanted Cause youve taken her for granted And everything you have got destroyed But youre just a boy,thanks,
