最早记得语法书和XDF讲过not、no这种明确的否定句才可以把and改为or，但是做了很多题之后，发现并不是这样的，例如
Seldommore that 40feet wide and 12 feet deep, but it ran 363 miles across the rugged wilderness of upstate New York, the Erie Canal connected the Hudson River at Albany to the Great Lakes at Buffalo, providing the port of New York City with a direct water link to the heartland of the North American continent.
A. Seldommorethan40feet wide and 12 feet deep, but it ran 363 miles across the rugged wilderness of upstate New York, the Erie Canal connected
B. Seldommorethan40feet wide or 12 feet deep but running 363 miles across the rugged wilderness of upstate New York, the Erie Canal connected
C. It was seldommorethan40feet wide and 12 feet deep, and ran 363 miles across the rugged wilderness of upstate New York, but the Erie Canal, connecting
D. The Erie Canal was seldommorethan40feet wide or 12 feet deep and it ran 363 miles across the rugged wilderness of upstate New York, which connected
E. The Erie Canal, seldommorethan40feet wide and 12 feet deep, but running 363 miles across the rugged wilderness of upstate New York, connecting
本题答案B，答案我没有问题，但是这句话是seldom在句中，and变成了or
再例如
Although energy prices have tripled in the
United States over the last two years, research indicates few people to have significantly reduced the amount of driving they do, nor are they making fuel efficiency a priority when shopping for cars.
few people to have significantly reduced the amount of driving they do, nor are they making
few people having significantly reduced the amount of driving they do or made
that there are few people who have significantly reduced the amount of driving they do, nor having made
that few people have significantly reduced the amount of driving they do and are not making
that few people have significantly reduced the amount of driving they do or made
正确答案：E，且不看其他方面的问题，E中只有few，将and变成or来使用了
来看一道符合XDF说法的题目：
The commission has directed advertisers to restrict the use of the word "natural" to foods that do not contain color or flavor additives, chemical preservatives, or nothing that has been synthesized.
(A) or nothing that has been
(B) or that has been
(C) and nothing that is
(D) or anything that has been
(E) and anything
本题答案：D，原句中出现了not——导致and变成了or
但是三道题如果从逻辑翻译的角度，可以感觉到，无论是not，no简单否定句，还是never，few，seldom这种否定句，采用or就是二选一，或者三选一（也就是常说的并集），如果采用and就是全部否定（交集），按照语义来讲，确实是or优于and。
三个句子都没有语法问题。关键看作者的意图是什么，其中AB是完全对立的。C可能有交集。
如果作者的意图就是C，你就要用I don't like fruits and vegetables.
你要用I don't like fruits or vegetables就改变作者意图了。作者: hoyancyn 时间: 2013-4-28 06:20
