2.were型虚拟式：
所谓were型虚拟式，就是借用行为动词过去时的某个形式以及be动词的"were"这个形式来表达某种虚拟的语气。
由于were型虚拟式主要用在if非真实条件句中，而且它是其他were型虚拟式句型的基础，所以我们先要搞清楚if非真实条件句。
(1) if非真实条件句:
条件句分为真实条件句和非真实条件句：
真实条件句是指真实的或可以实现的条件句，例如：If we work together, we are sure to finish the task in time. (如果我们大家一起努力，就一定能按时完成任务)，动词使用的是真实的时态和形式。
非真实条件句是指对已经发生过的事情，或对不可能发生或实现的事进行假设，例如："如果当时有医生在，这个孩子就有可能得救了"，显然，这是对已发生的事情的一种假设，该句的英语表达为：If there had been a doctor available, the child might have been saved.
为了便于理解和记忆，我们用表格形式加以归纳：
|
时间 |
动词形式 |
举例 |
|
过去 |
if条件句：had done / had been
结果句：would have done / been |
If there had been a doctor available, the child might have been saved.
倒装：Had there been a doctor available, the child might have been saved |
|
现在 |
if条件句：did / be动词用were
结果句： would do （be） |
If I were you, I would accept his offer. （如果我是你的话，我就接受他的提议。）
倒装：Were I you, I would accept his offer.
If I knew the fact, I would tell you. （我要是知道，我就会告诉你）
不可以倒装 |
|
将来 |
if条件句：
should do （be） / were to
结果句：would do （be） |
If it should rain tomorrow, we would stay at home. （一旦明天下雨，我们就呆在家里。）
倒装：Should it rain tomorrow, we would stay at home.
If he were to come this evening, I would ask him to help solve the problem. （要是他晚上会来，我就请他帮助解决这个问题。）
倒装：Were he to come this evening, I would ask him to help solve the problem. |
这里关键是要掌握好两点：
(A) 虚拟行为或状态发生的时间：过去?现在?还是将来?
(B) 采用了什么相应的动词形式?
补充说明：
(A) 当 "if "省略后，要采用倒装形式，如举例所示;
(B) 如果所说的条件是永远不可逆转的。如"如果我是你的话"(我永远不可能变为你)，即使是对过去的假设，也用"现在"虚拟式表示，例如：
If I were you, I would have taken his advice. (要是换了我，我就采纳他的意见了。)
(C) 结果句中的would 可以根据内容需要，使用might, could或should，例如：If she had known that you were there, she might have come.(要是她知道你在哪儿，她或许会来的。)但是"将来"虚拟式条件句中的should是将来时的"标志词"，不能用would代替，不要搞错了。
(D) 关于含蓄虚拟式：含蓄虚拟式是指虚拟的条件用一种比较含蓄的方式加以表达的虚拟语气，如："我昨天很忙，要不就来参加你的生日派对了".其中的"我很忙"是真实情况，"要不就来参加你的生日派对了"则是虚拟的：I was very busy yesterday, or I would have come to your birthday party.
所以，注意句子中出现的：but, or(否则), otherwise(否则), without(要不是),with(要是有)，but that(要不是), but for(要不是), if it were not for / 过去：if it had not been for(要不是 ) 等用来引出含蓄虚拟式的词或短语，例如：But for (或without) your cooperation, we would not have completed the experiment so smoothly.(要不是你们的合作，我们不可能那样顺利地完成这个实验。)
(2) were型虚拟式的其他用法 (同样要遵守"过去、现在、将来"的虚拟规则)：
●wish宾语从句：
I wish that he had not made so much fuss about it.(真希望他不要把那事搞大了。- 过去)
I wish that I were a doctor. (我希望我是个医生就好了。- 现在)
(注：这个句型中也可以用I wish that I was a doctor.)
I wish that the rain would stop. (真希望雨能停下来。将来)
●If only…(要是…就好了)
If only you hadn't offended him. (你当时不惹他就好了。- 过去)
If only I had some money on hand now. (我现在手头有些钱就好了。-现在)
If only he could come tomorrow. (他明天能来有多好啊。-将来)
●It is (about / high) time that….(是…的时候了)
由于该句型只能用在"现在"时间，所以从句的动词只能是"过去时"形式，例如：
It is high time (that) we began to work. (咱们该开始工作了。)
●As if (though)…(似乎…)
这个句型可以是陈述语气，也可以是虚拟语气。虚拟语气的时态变化原则与"wish"用法相同，例如：
She loves the children in the kindergarten as if they were her own. (她象自己孩子一样热爱幼儿园的孩子门。 - 现在)
He talked about China as if he had been there. (他谈起中国来好象去过那里。)
It looks as if it is going to rain.(看来天要下雨。- 陈述语气)
●Would (had) rather, would just as soon, would sooner, would prefer + 从句结构
这几个句型都表示一种"婉转的责备"，中文常有"还不如…"，"宁可…""倒希望…"等意思，例如：
I'd rather she stayed at home in such a bad health condition. (她身体这么差，我倒希望你呆在家里。- 现在)
I would just as soon you had returned him the money yesterday. (你还不如昨天就把钱还给他了。- 过去)
I would prefer he didn't stay there too long. (我倒不希望他不要在那儿呆得时间太长。)
比较：
I would prefer that she act the young lady. (我倒认为她演哪个年轻女子比较合适。- 表示建议，用 "should型虚拟式")
做虚拟语气的题目，归纳起来就是两句话：
一是，看清是什么形式的虚拟式，"should型"还是 "were型"?
二是，如果是were型虚拟式，看清句中所给的时态："过去"、"现在"、"将来"?
这里的关键是：要对构成虚拟语气的词、词组和句型比较敏感。
