Piece- and group-words: a blade of grass; a bunch of flowers
Uncountable nouns: pieces
To talk about a limited quantity of something we can use a word for a piece or unit, together with of, before an uncountable noun. The most general words of this kind are piece and bit. Bit (informal) suggests a small quantity.
- a piece/bit of cake/bread
- some pieces/bits of paper/wood
- a piece/bit of news/information
Other words are less general, and are used before particular nouns. Some common examples:
- a bar of chocolate/soap
- a blade of grass
- a drop of water/oil/vinegar
- a grain of sand/salt/rice/corn/dust/truth
- an item of information/news/clothing/furniture
- a length of material
- a loaf of bread
- a lump of sugar/coal
- a sheet of paper/metal/plastic
- a slice of bread/cake/meat
- a speck of dust
- a stick of dynamite/chalk/celery
- a strip of cloth/tape/land
not a … of …
Some words for small pieces can be used in a negative structure meaning ‘no … at all’.
- There’s not a grain of truth in what he says.
- There hasn’t been a breath of air all day.
- We haven’t got a scrap/bite (of food) to eat.
- He came downstairs without a stitch of clothing on.
Pair
Pair is used for many things that normally go in twos, and with plural nouns that refer to some two-part objects (see here).
- a pair of shoes/boots/socks/earrings
- a pair of glasses/binoculars
- a pair of trousers / jeans / shorts / pyjamas / leggings / tights (BrE) / pantyhose (AmE)
- a pair of scissors/pliers/tweezers
Plural nouns: collections
Special words are used before certain plural nouns to talk about groups or collections.
- a bunch of flowers
- a crowd of people
- a flock of sheep/birds
- a herd of cattle/goats
- a pack of cards (AmE a deck of cards)
Set is used before many uncountable and plural nouns referring to groups which contain a fixed number of things.
- a set of napkins / dishes / cutlery (AmE flatware / silverware) / spanners (AmE wrenches)
For a bit as a modifier before adjectives and adverbs, (see here).
For an amount, a lot, a large number, etc, (see here).
For sort, type, kind, etc, (see here).