Fewer and Less 的用法比較說明
Fewer and Less 的英文文法
形容詞 fewer 是 few 的比較級，less 是 little 的比較級。fewer 後面接複數名詞；less 後面接不可數名詞。
We usually use less with uncountable nouns. We use fewer with plural nouns:
I do less work at weekends than I used to.
Better cycle routes would mean fewer cars and fewer accidents.
Fewer people than we expected attended the party.
Should you wash your dishes by hand, or does the dishwasher use less water?
Fewer 和 Less 分別為 few 和 little 的比較級，few 後接複數可數名詞，little 後接不可數名詞。但 few 跟 a few 的用法並不相同，few 意為「(少之又少) 幾乎沒有」，表否定，而 a few 意為「一些」，表肯定。Little 和 a little 的用法亦有如此的差異，little 意為「(少之又少) 幾乎沒有」，表否定，而 a little 意為「一些」，表肯定。例如：
Allen has few friends in Tokyo, does he? (艾倫在東京幾乎沒有朋友，對吧?)
Allen has a few friends in Tokyo, doesn’t he? (艾倫在東京有一些朋友，不是嗎?)
Mary got little help from John, did she? (瑪麗沒有從約翰那兒得到什麼幫助，對吧?)
Mary got a little help from John, didn’t she? (瑪麗從約翰那兒得到一些幫助，不是嗎?)
Few 可當代名詞和形容詞用，fewer (及最高級 fewest) 亦然。但 little 和 less (及最高級 least) 除了用作代名詞和形容詞外，還可當副詞用。例如：
Sam ate little, so I urged him to eat a little more. (山姆幾乎沒吃，所以我勸他多吃一些) － 句中的 little 和 a little 都是副詞用法。
I had fewer books than he did. (我擁有的書比他少)
I drank less coffee than she did. (我喝的咖啡比她少)
Eat less or you’re getting fatter and fatter. (吃少點，否則你會越來越胖) － 句中的 less 為副詞用法。
Fewer 欠缺的副詞用法，正是它經常被用錯的癥結所在，尤其是在 fewer than 的比較句型中。在「形容詞/副詞比較級 + than」的句型中，若主動詞為 BE 動詞，須使用形容詞比較級 + than，若主動詞為普通動詞，則須使用副詞比較級 + than。由於 fewer 僅能用作形容詞，不能當副詞用，因此它不是位在 BE 動詞或連綴動詞之後，就是位在名詞之前。例如：
Cars made in Korea are fewer than those made in Japan. (韓國車比日本車少)
He worked fewer hours than I did. (他的工作時數比我少)
所以，問題中的句子只能使用 less than，不可使用 fewer than，因為 less 是副詞，而 fewer 是形容詞：
Less than 200 people went to the party. (參加派對的人數不到兩百人) (正)
= Fewer people than 200 went to the party.
Fewer than 200 people went to the party. (誤)
如果你曾經像這樣用錯 fewer than 而被老師或指導教授責備，現在應該可以釋懷了，因為連英國人都會用錯，何況我們大多數人只是第二語言學習者。英國《太陽報》(The Sun) 2012 年 4 月初有一篇關於雙子宮婦女兩個子宮同時受孕懷雙胞胎的報導；該報在報導中使用了下面這個令筆者無言以對的句子：
Research shows fewer than 100 women worldwide have fallen pregnant with twins in separate wombs. (研究顯示，全世界兩個子宮同時受孕而懷雙胞胎的雙子宮婦女不到百人)
然而，no fewer than (不少於，至少 － 用於數字前，表示強調) 是固定用法，似乎不受上述語法的規範 (或許是一直用錯而不自知)，因為在若干英文辭典和正式文件中不時可見類似下面的句子：
There shall be no fewer than three guards on duty. (值班警衛不得少於三人)
No fewer than 50 celebrities went to the concert. (至少有 50 位名流出席音樂會)
The stadium holds no fewer than 100,000 people. (這個體育場能容納至少 10 萬人)
When we use fewer or less before articles (a/an, the), demonstratives (this, that), possessives (my, your) or pronouns (him, them), we need to use of. We use less of with singular nouns and fewer of with plural nouns:
It was funny to begin with, but as time went on, it became less of a joke.
In ten years’ time, more and more people will be demanding information twenty-four hours a day, from all parts of the world. Fewer of them will be getting that information from newspapers which arrive hours after the news has occurred.
The basic rule for precise use of “less” and “fewer” is simple (though we slip often). Use “fewer” with countable, individual things, and “less” with uncountable amounts, volumes, etc. So: “I should drink less coffee,” but “I should eat fewer doughnuts.”
But it’s not as simple as plural (fewer) vs. singular (less). Sometimes “less” is correct even with a plural noun. The Times’s stylebook says this:
Also use less with a number that describes a quantity considered as a single bulk amount: The police recovered less than $1,500; It happened less than five years ago; The recipe calls for less than two cups of sugar.