21.　 像afraid, alive, awake, asleep, alone以“a”开头的形容词，一般不能用very修饰。

20.　 very, much, very much

very可修饰形容词及副词，不能直接修饰动词，修饰动词时，要用much或very much；much除了修饰动词外，还可修饰形容词或副词的比较级及过去分词；very much也可修饰过去分词：

The novel is very good./ This novel is much better than that one. / Her Japanese is improved very much.

19.　 ago, before

A “时间段+ago”表示从现在往前推算的“一段时间以前”，而“时间段+before”表示从过去某时刻再往前推算的“一段时间以前”。因此，前者常与一般过去时连用，后者常与过去完成时连用。He bought a violin a week ago. From his letter I knew that he had bought a violin a week before

B before可表示不确定的过去，而ago则不能： Have you been there before?

18.　 so，neither，nor

so可用在“so+助动词+主语”的倒装结构中，表示“也”，位置在助动词前，so的这种用法只能在肯定句里名胜；在否定句中用neither或nor，结构相同，表示“也不”。

He has seen the film. So have I .

Jim doesn’t like the novel. Neither (Nor) does Linda.

17.　 faily，rather，quite

A三者都可以修饰形容词和副词，都有“相当”的意思，但failry词义最弱，quite稍强，rather最强。Fairly一般表示肯定、褒义，rather有时表示否定、贬义。It is fairly cool today. It is rather cold today.

B quite和rather可以修饰动词，而fairly不能。

　 I don’t quite understand what you said./ I rather like the song.

16.　 too，also，as well，either

前三者意思相近，一般不用于否定句中，否定句中用either。Too常位于名末，也紧接在主语后面；also一般用于肯定句和疑问句中，位于be动词、情态动词、助动词之后，实义动词之前；as well一般位于句末；either也一般位于句末。

They grow cotton, too./ He his also interested in computers./ He is a teacher, and a poet as well./ You didn’t go and she didn’t go, either.

15.　 already，yet，still

already一般用于肯定名，也可用于预料能得到肯定回答的疑问句中，表示某事已发生；yet一般用于否定句或疑问句中位于句末，意为“还，已经”；still一般用于肯定句，也可用于疑问句，意为“仍然，还”。

I have already read the book./ We haven’t made speeches yet./ Is my skirt dry yet?/ I still hope to get some advice from you on my studies.

14.　 特殊用法：

13.　 同一人或物，比较其两种性质或状态，不管形容词是单音节或多音节，一律用more…than：He is more wise than diligent。

12.　 比较级前可用MANY,MUCH,FAR,A BIT, A LITTLE, A GREAT DEAL OF, A LOT等词表示程度或差别。