【知识点详解】
1. 情态动词+have done 的用法:
- could have done 表示过去可能发生的情况,常用于否定句和疑问句,例如:I couldn't have imagined... (我从未想过...)
- must have done 表示对过去情况的肯定推测,例如:He must have studied last night. (他昨晚一定学习了)
- should/ought to have done 表示本应做而未做的事情,带有批评或责备意味,例如:You should have told me earlier. (你本应该早点告诉我)
- shouldn't/oughtn't to have done 表示本不该做但实际做了的事情,同样带有责备意味,例如:You shouldn't have cheated in exams. (你不应该在考试中作弊)
- needn't have done 表示没有必要做但实际上做了的事情,含有后悔或责备,例如:You needn't have bought such an expensive watch for her. (你没必要给她买那么贵的手表)
- can't/couldn't have done 表示过去一定没有发生的事情,例如:I can't have seen the film. (我一定没看过这部电影)
- may/might have done 表示对过去情况的不确定推测,例如:He might have gone to the library. (他可能去了图书馆)
2. such 和 so 的用法区别:
- such + a/an + adj. + n. 用于单数可数名词前,例如:such a beautiful girl (如此美丽的女孩)
- such + adj. + n. 或 n. [pl.] 用于不可数名词或复数名词前,例如:such clean water (如此清澈的水),such interesting books (如此有趣的书)
- so + adj. + a/an + n. 也用于单数可数名词前,例如:so beautiful a girl (如此美丽的一个女孩)
- so many/few + n. [pl.] 用于复数名词前,例如:so many people (如此多的人),so few errors (如此少的错误)
- so much/little + n. [U] 用于不可数名词前,例如:so much rain (如此多的雨)
- 注意:当such与数量形容词连用时,置于其后,例如:no such man, many such books
3. 定语从句中的关系代词:
- which 在非限定性定语从句中引导并指代先行词,例如:This gift was the Amber Room, which was given this name...
- 先行词在从句中作主语时,可以用which/who,例如:The chairman, who spoke first...
4. 介词后的定语从句:
- 在某些介词后,如in, on, at等,引导非限定性定语从句通常使用which,例如:On April 1 they flew to Beijing, where they stayed several days.
以上是针对人教高中英语必修二unit language points中的核心语法点的详细解释,包括情态动词+have done的用法以及such和so的用法差异,还有定语从句中关系代词的应用。这些知识点对于学习和理解英语中的过去事件推测、表达程度以及复杂句子结构至关重要。