在中，单独考察的题几乎没有，但是语法知识点却贯穿整张试卷，下面是小编为大家整理的英语四级语法知识，希望可以为大家带来帮助，一起来学习一下吧。
　　 16.4 虚拟条件句的倒装 虚拟条件句的从句部分如果含有were, should, 或had, 可将if省略，再把were, should或had 移到从句句首，实行倒装。 Were they here now, they could help us. =If they were here now, they could help us. Had you come earlier, you would have met him =If you had come earlier, you would have met him. Should it rain, the crops would be saved. =Were it to rain, the crops would be saved. 注意： 在虚拟语气的从句中，动词'be'的过去时态一律用"were"，不用was， 即在从句中be用were代替。 If I were you, I would go to look for him.
　　如果我是你，就会去找他。 If he were here, everything would be all right. 如果他在这儿，一切都会好的。 典型例题 _____ to do the work, I should do it some other day. A. If were I B. I wereC. Were ID. Was I 答案C. 在虚拟条件状语中如果有were, should, had这三个词，通常将if省略，主语提前, 变成 were, should, had 主语的形式。但要注意，在虚拟条件状语从句中，省略连词的倒装形式的句首不能用动词的缩略形式。如我们可说 Were I not to do., 而不能说 Weren't I to do.