语法知识
一、虚拟语气Subjunctive mood
虚拟语气:表示说话人的主观愿望、假设、怀疑或推测等 （一）虚拟语气在简单句中的用法
1 虚拟语气可用在口语中，使语气显得比较客气委婉。通常谓语由“should, would, could, might加动词原形”构成 1）陈述自己的看法
I should like to have a talk with you. I would like to say a few words about it. 2）提出请求或邀请
Would you mind opening the door? Could you come and see me tomorrow? 3）提出建议或劝告
You might as well tell me the truth. You’d like some coffee, wouldn’t you? 4）提出问题
What would you advise me to do? Could you tell me your telephone number?
2 虚拟语气可用于简单句中，表示祝愿、诅咒、禁止或命令等 1）用动词原形
Long live the Communist Party of China! 中国共产党万岁！ God bless you! 愿上帝保佑你！
God damn you! 该死的！ Heaven forbid! 上天不容！
Somebody fetch a basin of water. 谁去打盆水来。 Everybody come in! 大家都近来！ 2）may用于句首，动词用原形 May you be happy! May you succeed!
（二）虚拟语气在if条件状语从句中的用法 1对现在情况假设，即与现在事实相反 主句--情态v.+ v.原形 从句--v.过去式(be→were)
2对过去情况假设, 即与过去事实相反 主句--情态v.+ have done(v.现在完成式) 从句--had done (v.过去完成式)
3对将来情况假设，即将来不太可能实现的情况 主句--情态v.+ v.原形 从句--①v.过去式（be→were） ②should + v.原形 ③were to + v.原形
虚拟语气中常用情态动词为：would, should, might, could Eg. If they had time, they would study Russian, too. If I were you, I should go and see the doctor at once.
I could have met her if I had come a few minutes earlier. If she hadn’t got up late, she wouldn’t have been late for school. If it rained tomorrow, the sports meet would be put off. If it should rain tomorrow, the sports meet would be put off. If it were to rain tomorrow, the sports meet would be put off. ① 省if
在书面语和正式文体中，从句中有were, should, had 可省if，把were, should, had放/提到主语之前。
Eg. If it were not for their support, we would be in a ve