a lot of ,a few ,a litte點用?

a few 是可以數到(countable),意思是 幾個、一些 (some but not many)

只可以用在數到的物件和人度 e.g. a few grapes, a few boys, a few girls 等等

a little 是不可數的(uncountable),意思是 一些,小量 (not very mouch)

只可以用在不可以數的東西 e.g. a little food, a little milk, a little water 等等

a lot of 是可以用在數到同不可數的物件上, (countable, uncountable)

意思是許多 (a large number of) e.g. a lot of girls, a lot of bees, a lot of people 等等

Few and little

We use a few with plural, countable nouns. For example, "A few people came to the party."

We use a little with uncountable nouns. For example, "There's a little coffee left, if you would like some."

We can also use few and little (without "a") to mean very few or very little (i.e. much less in quantity).

For example, "There's little point in calling" (= there's not much point calling).
"There were few people at the concert."

"A few" is more in quantity than "few"; and "a little" is more in quantity than "little".
"Few people understand" (not many people understand), compared to "a few people understand" (some people understand).

In spoken English, we can also say not many, or only a few to mean "few" and only a little or not much to mean "little".
"Not many people came to the party." Or "Only a few people came to the party."
"There was only a little petrol left in the car." Or "There wasn't much petrol left in the car."

Making comparisons

The comparative form of "few" is fewer, and the comparative form of "little" is less.

Remember: use "fewer" for plural, countable nouns, and "less" for uncountable nouns.
For example, "There are fewer people here than last year" or "He drinks less coffee than I do".

It is grammatically incorrect to say "There are less people here than last year", as "people" is a plural countable noun.

2013-01-02 17:07:20 補充：
由於字數限制，我打不了ＬＯＴＳＯＦ那一段

2013-01-02 17:08:25 補充：
Lots of and a lot of
In spoken English we often use lots of or a lot of. In written English, it is more common to write many (for countable plural nouns) or a great deal of (for uncountable nouns) in positive statements.