A FEW AND FEW

Examples:

1) She has been here only two weeks, but she has made a few friends.
(Positive idea: She has made some friends)

A few gives a positive idea; they indicate that something exists, or is present.

2) I feel sorry for her. She has (very) few friends.
(Negative idea: She doesn't have many friends; she has almost no friends.)

Few gives a negative idea; they indicate that something is largely absent.

--

1) My father went to the dentist at 4 and he found few cavities. 
Few = not many.  My teeth are in relatively good condition.

2) My father went to the dentist at 4 and he found a few cavities.
A few = several.  My teeth are in somewhat poor condition.

--

1) He saw a few girls at the mall.
(He saw two or three girls at the mall.)

2) Asif has few friends because he is a rude boy.
(Asif has almost no friends because he is a rude boy.)

--

1) She has a few minutes to wait before she goes to school.

2) I have few minutes left to eat my sandwich before the peon rings the bell.


Cheers!
Naeem

Source(s):
Understanding and Using English Grammar