含義不同、用法不同。more的意思為更多的、更大的，可作副詞，后面可接可數(shù)或不可數(shù)名詞；less意為更少的，后接不可數(shù)名詞，也可以用來修飾動詞、形容詞和副詞；fewer意為較少的、幾乎沒，表示否定的意思，后接可數(shù)名詞。

He'd like more time to think things over.

他希望有更多的時間把情況考慮周詳。

Now she won't have to go out to work any more.

現(xiàn)在她不必再出去工作了。

How much will it cost, more or less?

這個大概得花多少錢？

It is less of a problem than I'd expected.

問題不像我預(yù)料的那么大。

Fewer people write with their left hand than with their right.

用左手寫字的人比用右手的人少。

There seem to be fewer tourists around this year.

今年來訪的旅游者似乎少了。