The quantifiers a little and a few have a positive meaning. They refer to a small quantity or number.

Little and few, on the other hand, have negative meanings. They show insufficiency. If you have little knowledge, you don’t have enough knowledge.

The quantifier much is mainly used in questions and negatives. However, much of can be used in affirmative sentences as well.

Much of his wealth went to charitable institutions.

I didn’t do much work yesterday. (BUT NOT I did much work yesterday.)

We are more likely to express that idea using a lot of or a great deal of.

I did a lot of work yesterday.

Did you eat much food?

The quantifier most is used before a noun without a determiner.

Most criminals are non-violent.

Before a noun with a determiner, we use most of.

Most of the applicants had a post graduate degree. (NOT Most the applicants…)

Most students hate grammar. However, most of the students in my class enjoy learning it.

The indefinite article a/an is sometimes used with many. This structure takes a singular verb.

Many a sailor has died at sea. (NOT Many a sailor have died at sea.) (NOT Many a sailors have died at sea.)

Many a young man has fallen in love with her blue eyes.

Note that this construction should be used sparingly.

Predeterminers

The predeterminer goes before other determiners. This class of words includes multipliers (double, twice, three/four times . . . .); fractional expressions (one-third, three-quarters, etc.); the words both, half, and all; and intensifiers such as rather, quite, and such.