3.20 few, little, a few, a little (a) few + 可数名词, (a) little + 不可数名词 a few / a little 为肯定含义，还有一点 few / little 为否定含义，没有多少了。 He has a few friends. 他有几个朋友。 He has few friends. 他几乎没有朋友。 …...

19.9 比较until和till 此两个连词意义相同。肯定形式表示的意思是"做某事直至某时"，动词必须是延续性的。否定形式表达的意思是"直至某时才做某事"。动词为延续性或非延续性都可 以。 正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还…...

19.4 目的状语从句 表示目的状语的从句可以由that, so that, in order that, lest, for fear that, in case等词引导，例如： You must speak louder so that /in order that you can be heard by all. He wrote the name down for fear that(les…...

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 ea…...

9.2 分词作状语 As I didn't receive any letter from him, I gave him a call.- Not receiving any letter from him, I gave him a call. 由于没有收到他的信，我给他打了电话。 If more attention was given, the trees could have grown better…...

19. 状语从句 19.1 地点状语从句 地点状语从句通常由where, wherever 引导。 Where I live there are plenty of trees. 我住的地方树很多。 Wherever I am I will be thinking of you. 不管我在哪里我都会想到你。 ...

19.6 条件状语从句 连接词主要有 if, unless, as/so long as, on condition that 等。. if 引导的条件句有真实条件句和非真实条件句两种。非真实条件句已在虚拟语气中阐述。 unless = if not. Let's go out for a walk unless you are too tire…...

19.1 地点状语从句 地点状语从句通常由where, wherever 引导。 Where I live there are plenty of trees. 我住的地方树很多。 Wherever I am I will be thinking of you. 不管我在哪里我都会想到你。 ...

11.22 一般现在时代替将来时 时间状语从句，条件句中，从句用一般现在时代替将来时When, while, before, after, till, once, as soon as, so long as, by the time, if, in case (that), unless, even if, whether, the moment, the minute, the day,…...

3.13 none, few, some, any, one, ones 一、 none 无 1) none作主语，多与of 构成短语 none of。 在答语中，none可单独使用。 Are there any pictures on the wall? None. 2) none作主语，谓语动词单复数均可。但如做表语，则其单复数与表…...