How to say one in English?

1 TV set A TV set

1 sofa set sofa

1 apple an apple

1 pen A pen

1 documentation

1 bunch of flowers, bunch of flowers

1 a pair of shoes, a pair of shoes

1 Cake A piece of cake (also meaning "something")

1 hand sand

1 copy of the morning paper

1 clicks

1 water drop

etc