书上说：虚拟语气中，不管主语是单数还是复数，动词 be 一律都用 were，但主语是单数时有时也可用 was。但仿佛有的状况下是需要要用 were 的（即不可以用 was），譬如 If I were you（假如我是你的话）。请问：在什么状况下，虚拟语气中的单数主语后面需要要用were（不可以用was）？谢谢！
关于虚拟条件句中 was 与 were 的使用方法问题，下面是一个小总结，期望对这位网友有所帮助：
▲在虚拟条件句中，若主语是I / he / she / it 等单数形式之后，其后的动词 be 可用 were代替 was。两者在乎义上没不同，但 were 更为正式，尤其是在陈述心存怀疑的事情时：
If I were / was any richer, Id buy ayacht. 假如我有点儿钱，我就买艘游艇。
If I were / was better qualified, Id applyfor the job. 假如我的条件好一些，我就申请那份工作了。
然而在陈述纯粹想象的事情时，were 更为常用。如：
If I were a bird, I could fly to you. 假如我是只鸟，我就会飞到你身旁。
If I were a man they would have given methe job. 我如果男的，这份工作就准给我了。
▲在 If I wereyou / If I were in your position 这种表达，最好不需要 was。这类说法常常用于提出建议。如：
If I were you, I would go. 我如果你，我就会去。
If I were in your position, I would accepttheir offer. 假如我处于你的地位，我会同意他们的条件。
此使用方法用于除第二人称以外的人称也是这样。如：
If I were Jane / in Janes position, Idwalk out on him. 假如我是珍妮，我就会离弃他。
▲在 If it werenot for / Were it not for 这种结构中可以用 was 代替 were，但以用 were 更为常用。如：
If it werent / wasnt for your help, Iwould still be homeless. 若非你的帮忙，我仍会无家可归。
If it wasnt / werent for his wifes moneyhed never be a director. 假如不是他老婆的钱，他决不可能成为董事。
但若将 were 移至主语前而省略连词 if 时，则只用 were 而不需要 was。如：
Were I Tom I would refuse. 假如我是汤姆，我会拒绝的。
Were it not for your help, I would still behomeless. 若非你的帮忙，我仍会无家可归。
