1. Not all paragraphs have a topic sentence.（P24）
并不是所有的段落都有中心句。
英語中的部分否定（即不完全否定）有如下一些表示方法：
一、 all 的否定式：not all…（或：all…not）表示"并非都……"、"不是所有的都……"例如：
Not all men can be masters. (= All men cannot be masters.) 并非人人都能當頭頭。
Not all bamboo grows tall. 并非所有的竹子都會長很高。
二、 both 的否定式：not…both (或：both… not) "并非兩個……都……" 例如：
I don't want both the books. 我不是兩本書都要。
Both (the) windows are not open. 兩扇窗子并不都開著。
三、 every…的否定式："不是每……都……" 例如：
Not every book is educative. (或：Every book is not educative.) 不是每本書都有教育意義的。
Not everyone likes this book. 并非人人都喜歡這本書。
This flower is not seen everywhere. 這花并不是隨處可見的。
四、 always的否定式："并非總是（并非一直）……" 例如：
He is not always so sad. 他并不是一直都這樣悲傷。
五、 entirely, altogether, completely 和quite 的否定式："不完全……"，"并非完全……" 例如：
The businessman is never to be entirely trusted. 不可以完全信任商人。
He felt not altogether satisfied. 他并不完全滿意。
I don't agree completely. 我并不完全同意。
What he did was not quite proper. 他做的不十分妥當。
六、 all the time 的否定式："并非一直……"、"未必老是……" 例如：
A foolish man doesn't make a mistake all the time. 笨人未必老是犯錯誤。
七、 not…and…的否定式，被否定的往往是and后面的那一部分。 例如：
He did not speak clearly and correctly. 他講得清楚但不正確。
This film is not interesting and instructive. 這部電影有趣但無教育意義。
She cannot sing and dance. 她會唱歌但不會跳舞。
如果將and 換成or，not 對其后面的兩部分就全盤否定了。
He did not speak clearly or correctly. 他講的既不清楚也不正確。
如要對上述的all, both, every, always, 以及entirely, altogether, completely, quite 和 all the time 等詞作完全否定，那就分別要用與之相對應的全否定詞，如no, none, neither, no one, never, not (never)… at all 等。例如：
All of them can do it.--- None of them can do it.
Both are good.---Neither is good.
Everybody likes it. ---Nobody likes it.
He is always late. --- He is never late.
We don\'t trust them entirely. --- We never trust them at all.
He was here all the time. --- He was never here.
2. For decades, Florida has been attracting older residents.
Grammar point: present perfective progressive(現在完成進行時)
相關高考試題：
1.（2007 湖南）
Cathy is taking notes of the grammatical rules in class at Sunshine School, where she _____ English for a year.
A. studies B. studied C. is studying D. has been studying
2.（2007 江西）
-I have got a beadache.
-No wonder. You in front of that computer too long.
A. work B .are working C. have been working D. worked
3. 2006湖北）
I won't tell the student the answer to the math problem until he ____on it for more than an hour.
A. has been working B. will have worked
C. will have been working D. had worked
答案及解析：1. D 2. C 3. A