求详解英语语法be-型虚拟式,急

你问的不对吧,虚拟语气又称“非真实条件句” 即对不可能发生的事情假设.例如 if I were you.事实是 你不可能成为他,所以这个被称为虚拟句.相反If it is fine tomorrow,we will go toXX..这个事条件句 ,因为它是对可能发生的事情进行假设.( 明天天气好不好 ,就目前这个状况是不能肯定说 的.） 虚拟条件句 一般的呢 分从句 和主句 ,主句的现在时态,一般将来时态都可以采用 sould would (couldmight也行,不过通常不是用这个) + 动词原形.从句的一般时 用动词(过去式) 注意 不是过去分词哦.如果是BE 采用were
instance:
If I knew his telephone number,I would tell you.
从句将来时可采用 三种方式
if+主语+were to do
if+主语+should+do
if+主语+did（动词过去式）/were
If she were to be here next Monday,I would tell her about the accident.
从句是过去式 用had done ,主句用wouldshould have done
If he had taken my advice,he would not have made such a mistake.
还要注意 就是当 其句中动词 或者是形容词 含有,建议、命令、要求、目的 都使用虚拟句（你肯定见过这类句子,只不过一般省略了shouldwould）
一想要(desire) 一宁愿(prefer) 一坚持(insist)二命令(order ,command) 三建议(advise ,suggest ,propose/recommend) 四要求(demand ,require ,request ,ask)
They recommend that this tax（should） be abolished
注意 当 suggest,insist.这俩个次用于表示 坚持,暗示的建议,
不可以使用虚拟语气
he insist that he is innocent.
另外 还要注意 一个倒装结构,那就是如果if 引导的虚拟句中 有 were should had 可以省略,并将动词提前.
were i scientist,I could help him.
（ 不懂在问）