大学英语六级语法知识非真实条件句

　　在大学英语六级考试中，单独考察语法的题型几乎是没有的，但是语法知识点却贯穿整张试卷，下面小编为大家整理了英语六级基础语法知识，希望对大家有所帮助。
　　英语知识：非真实条件句 时态：可以表示过去，现在和将来的情况。它的基本特点是时态退后。
　　a. 同现在事实相反的假设。
　　句型 ： 条件从句主句 一般过去时should( would) 动词原形 If they were here, they would help you.
　　b. 表示于过去事实相反的假设。
　　句型： 条件从句 主句 过去完成时 should(would) have 过去分词 If she had worked harder, she would have succeeded. The rice would not have been burnt if you had been more careful. If my lawyer had been here last Saturday, he would have prevented me from going. If he had come yesterday, I should / would have told him about it. 含义：He did not come yesterday, so I did not tell him about it. If he had not been ill and missed many classes, he would have made greater progress. 含义： He was ill and missed many lessons, so he did not make greater progress.

　　c. 表示对将来的假想
　　句型： 条件从句 主句 一般过去时 should 动词原形 were 不定式 would 动词原形 should 动词原形 If you succeeded, everything would be all right. If you should succeed, everything would be all right. If you were to succeed, everything would be all right.