如果你看到下列的句子，你会认为它们是正确的还是错的呢?

　　1.　I wish I were a bird.

　　2.　We request that you be here tomorrow.

　　也许你会说：“哈哈，第一句的I were 错了，应该是I was;而第二句中的you be是什么东东呀?不是you are, 也不是you will be, 什么you be?!”

　　其实上面的句子都是一种称为 Subjunctive 类型的句子。Subjunctive Mood 有的书译为“假设语气”，虽不很贴切;但在相当大的程度上，告诉我们这种句子的特点，Subjunctive Mood中文译作“虚拟语气”，似乎不及“假设语气”那么容易明白。它是一种动词形式，表示说话人的某种假设、愿望、怀疑、猜测、建议等含义。

　　基本上，虚拟语气可分为虚拟现在(Subjunctive Present)和虚拟过去(Subjunctive Past)两种;但它们和时态(Tenses)上所指的现在时态(Present Tense)和过去时态(Past Tense)是有所不同的。

　　一、虚拟现在(Subjunctive Present)

　　虚拟现在的句子，在任何时候都要用动词的原形(root form)，就算是第三人称(he, she, it)也是如此。如：

　　1.1　现在时态(Simple Present)

　　I work ---- I work

　　you work ---- you work

　　he works ---- he work (注意到了吗，是work，不是works)

　　she works ---- she work (不是she works 喔)

　　it works ---- it work　(同样不是it works 喔)

　　we work ---- we work

　　they work ---- they work

　　1.2　现在进行时态(Present Continuous)

　　I am working ---- I be working (注意用的是be，怪怪的!)

　　you are working ---- you be working

　　he is working ---- he be working

　　she is working ---- she be working

　　it is working ---- it be working

　　we are working ---- we be working

　　they are woring ---- they be working

　　1.3　现在完成时态(Present Perfect)

　　I have worked ---- I have worked

　　you have worked ---- you have worked

　　he has worked ----- he have worked (用的还是have喔)

　　she has worked ---- she have worked

　　it has worked ---- it have worked

　　we have worked ---- we have worked

　　they have worked ---- they have worked

　　1.4　现在完成进行时态(Present Perfect Continuous)

　　I have been working ---- I have been working

　　you have been working ---- you have been working

　　he has been working ---- he have been working　(是he have, 不是he has )

　　she has been working ---- she have been working

　　it has been working --- it have been working

　　we have been working ---- we have been working

　　they have been working ---- they have been working