很多英语学习者都觉得If引导的条件状语从句这个句型很难，学习起来很吃力。下面是我为你整理的If引导的条件状语从句的相关资料，希望大家喜欢!
If引导的条件状语从句用法1if引导的条件状语从句可以放在主句之前，也可以放在主句之后，如果放在主句之前，中间要用逗号将主句和从句隔开。
例如：
If I am free, I will come to see you
= I will come to see you if I am free
如果我有空，我就来看你。
2 在含if引导的条件状语从句的复合句中，主句用一般将来时，从句通常用一般现在时态表示将来意义，即“主将从现”原则。
例如：
If it snows tomorrow, we will go skiing
如果明天下雪，我们就去滑雪。
3 在含if引导的条件状语从句的复合句中，语句的谓语还可含有情态动词can、must、may等，主句也可是祈使句。
例如：
If it stops raining, we can go out
如果雨停了，我们就能出去。
4 在含if引导的条件状语从句的复合句中，如果主句部分描述的是客观事实或真理，要用一般现在时。
例如：
If you heat the ice, it turns into water
如果你加热冰，它就会变成水。
if引导的非真实条件句对过去的虚拟
条件从句(if):主语+had done 主句might/would/should/could+have done
对现在的虚拟
if+ 主语+动词过去式(be用were)主句 might/would/should/could+do
对将来的虚拟
if+主语+动词过去式(be用were)或主语+should do或主语+were to do
主句 might/would/should/could+do
eg
Tom got to the station in time because he started earlier
If Tom had started late, he would have missed the train
Do you think the thief entered through the door
No, if he had, I don't believe, he would have broken the living room window
If the book weren't so expensive, I would buy it
If you didn't live so far away, we would be able to visit you more
What would you do if you lost your passport in a foreign country
Why hasn't he come If he should not come on time, we would have to put off the trip
2注意事项
eg
If she hadn't work hard at English in the past, she wouldn't work as well as a secretary in a large company now 混合时间的虚拟语气 从句为对过去的虚拟，主句是现在。
Had we not used an out-of-date timetable, we wouldn't have missed the train
if引导从句的倒装从句相当于 if we had not used an out-of-date timetable, 同样，were还有should 在从句中都可以提前，省略if
If only 要是就好了
If only I were younger!
If only I had worked harder in my teenage years!
If only I should travel tomorrow!
虚拟语气的十大句型一、虚拟条件句：
条件状语从句是非真实情况，在这种情况下要用虚拟语气。
1条件从句与现在事实不一致，其句型为：
句型1：If +主语+过去时，主语+ should (could, would, 或might) +动词原形
(1) If I were you, I would study hard
(2) If it rained, I would not be here now
2条件从句与过去事实不一致，其句型为：
句型2：If +主语+had+过去分词，主语+ should(could, would, 或might)+ have +过去分词
(3) If the doctor had come last night, the boy would have been saved
(4) If I had not studied hard, I would have failed in the exam last term
3条件从句与将来事实不一致，其句型为：
句型3：If +主语+过去时/ should +动词原形/ were to+动词原形，主语+ should (could, would, 或might) +动词原形
(5) If it should rain tomorrow, we would stay at home
(6) If I were to go to the moon one day, I could see it with my own eyes
(7) If you missed the film tonight, you would feel sorry
注意问题：
1If条件句中绝对不可以出现would。
2根据句中的时间状语，有时可能出现“混合虚拟”的情况，即主句可能是现在的情况，条件句也许是发生在过去的情况，但都要遵守上述句型。如：
(8) If you had studied hard before, you would be a college student now and you would graduate from a college in four years’ time
3条件句中如果出现were, had, should可省去if，将主语与这些词倒装。例如：
(9) Had the doctor come last night, the boy would have been saved
(10) Were I to go to the moon one day, I would see it with my own eyes
(11) Should it rain tomorrow, we would stay at home
二、名词性虚拟语气：
在表示命令、建议、要求、惊叹时的名词性从句中需用虚拟语气，基本句型：
句型4：主语+(should)+动词原形
(12) Mother insisted that John (should) go to bed at 9 o’clock(宾语从句)
(13) It was required that the crops (should) be harvested at once(主语从句)
(14) It is surprising that she shouldn’t pass the math exam (主语从句)
(15) The suggestion that he (should) be invited was rejected(同位语从句)
(16) Their demand is that their wages (should) be increased(表语从句)
注意：在这种句子中绝不可以出现would, must, could等。
三、虚拟语气在一些特殊词中的使用或含蓄条件句：
句型5：wish后的宾语从句
与现在愿望不一致：主语+过去时;
与过去愿望不一致：主语+ had +过去分词 / could + have +过去分词;
与未来愿望不一致：主语+ would / could +动词原形。如;
(17) I wish I were you
(18) I wish I had visited the White House when I was in the States
(19) I wish I could meet you tomorrow at the party
句型6：It’s time句型(当It’s time后用that从句时应该为“主语+ should +动词原形”或“主语+过去时”)
(20) It’s time that you went / should go to school
句型7：If only引起的感叹句相当于“How I wish +宾语从句”
(21) If only he could come! 他要能来就好了。
(22) If only I had known the answer! 我要早知答案就好了。
句型8：would rather, as if(though)引导的句子也需使用虚拟，表示过去的情况用过去完成时，表示现在与将来的情况
用过去时。
(23) I’d rather you posted the letter right away
(24) I’d rather you had returned the book yesterday
(25) She loves the children as if they were hers
(26) Alan talked about Rome as if he had been there
句型9：without, but, but for, but that, otherwise引起的短语或句子常暗含着虚拟条件。
(27) Without you, I would never know him
(28) But for your cooperation, we wouldn’t have done the work so well
(29) But that she was afraid, she would have said no
(30) I would be most glad to help you, but I’ am busy now
(31) I should have come to the party yesterday, but I was busy
(32) I am busy now; otherwise I would do you the favor!
句型10：If it were not for / If it hadn’t been for (要不是因为……)，其后面的主句也需使用虚拟。
(33) If it were not for his help, I wouldn’t go home now
(34) If it hadn’t been for the determined captain, all the passengers on the board wouldn’t have been saved
条件状语从句表示主句的动作发生的条件、假想、推测或意愿。用连词
if,
unless
和起连接作用的短语
except
that;
in
case
that;
on
condition
that;
provided/providing
that;
so/as
long
as;
suppose/supposing
that
引导。
用法：
1从句表示的条件客观上是现实的，常用陈述语气，如：
If
the
stamp
is
torn,
it's
no
good
for
my
collection如果邮票是破的，那我收集起来就没有用了。
Suppose
all
the
doors
are
locked,
how
will
you
get
into
the
house
假如所有的门都锁上了，你怎么会进到这所房子呢？
2从句表示的条件同事实相违背或不可能实现，通常用虚拟语气。如：
If
I
were
captain
of
a
ship,
I
would
take
you
on
a
voyage
round
the
world如果我是一艘轮船的船长，我将带你航海环游世界。
注意事项：
1用一般现在时表示将来时。
The
meeting
will
be
held
out
of
doors
unless
it
rains除非下雨，大会将在户外举行
2用选择完成时替代将来完成时。
If
I
have
made
a
mistake,
I
will
try
to
remedy
it如果我犯了错误，我将会努力改正
3will用在真实条件状语从句中是情态动词，表示意愿或决心，而不是单纯表示将来。
I
will
tell
you
if
you
will
come
on
Friday如果你愿意星期五来，我将告诉你。
还有其他一些情况，你暂时用不到，以后自己多注意。
条件状语从句三种时态是如下：条件状语从句的主句是一般将来时，从句用一般现在时。条件状语从句主句是祈使句，从句用一般现在时。条件状语从句主句是含有情态动词的一般现在时，从句多用现在进行时。条件状语从句if的条件状语从句遇到变换间接和直接时 , 祈使句应用not to。
条件状语从句的连接词主要有if，unless，as，so long as，on condition that等，if 引导的条件句有真实条件句和非真实条件句两种，非真实条件句已在虚拟语气中阐述。
在复合句中，由从句表示的状语叫做状语从句。它可以用来修饰主句中的动词·形容词·副词等。根据它表达的意思，状语从句可以分为时间状语从句，地点状语从句，条件状语从句，比较状语从句，目的状语从句，结果状语从句和让步状语从句等。
由连接词if或unless引导的状语从句叫做条件状语从句。（注意：在含有条件状语从句的复合句中，表示将来时态，主句是一般将来时态，从句要用一般现在时[主将从现原则])
1、由引导词if或unless引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后（状语从句中的动作），其它事情（主句中的动作）才能发生，通常译作“假如”、“如果”。
2、在含有条件状语从句的复合句中，表示将来时态，主句是一般将来时态，祈使句或情态动词，从句要用现在时态,[主将从现原则]。（主将从现，将并非指将来时，还指表示将来含义的，跟着if后的那句话是从句。）
分类: 教育/科学 >> 外语学习
问题描述:
什麽是条件状语从句？
解析:
条件状语从句就是用以表示“假设条件下会。。。”
常用if ,in case , on condition等词来引导
条件状语从句分真实条件句和非真实条件句
真实条件句，
如：If it rains tomorrow, we won”t go on a piic
非真实条件句是虚拟语气的一种，表示与事实相反，如：
If I were you, I would go with him
条件状语从句例句：
1、If you cheat in the exam you’ll never get away with it
考试作弊必予追究。
2、Unless you go at once you will be late
如果你不马上走，就会迟到的。
3、I’ll remember that day as long as I live
只要我活着，我就不会忘记那个日子。
4、In case I forget, please remind me about it
万一我忘记，请提醒我一下。
5、I don’t know if it will rain tomorrow But if it rains tomorrow, I’ll stay at home
不知道明天是否会下雨，但要是下雨的话，我就呆在家里。
条件状语从句的用法及规则：
1、引导条件状语从句最常用的连词是if，由if引导的条件状语从句表示在某种条件下某事很可能发生。
2、if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设，从句多用一般过去时或过去完成时。
3、在条件状语从句中，要注意“主将从现”的规定，即主句用一般将来时，从句用一般现在时表示将来时。
4、if既可以引导条件状语从句，表示“如果”，也可以引导宾语从句，表达“是否”。一站式出国留学攻略 >
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