Developing cohesion 

Substitution page 2 of 5

Using one/ones for nouns

One can substitute for a singular countable noun, and ones for a plural noun. One can stand on its own:

"Can I get you anything from downstairs?"
"Yes, as a matter of fact. I'll have a drink, I think. Bourbon. Rocks."
"Okay." He started out.
"And get yourself one too, if you want one," she called out. (Bank of English)

One can also be used in conjunction with a or the:

The truth is that Barbara loves being a grandmother but while she was in the White House she couldn't be a proper one. (Bank of English)

Next to Wally Taylor are two railway bridges, the very old and the new nestling side by side. The downstream one is the Albert Bridge, the oldest bridge still in use on the river, named after the late consort of Queen Victoria. (Bank of English)

However, ones needs another word or phrase to modify it:

You can get the really big bath sheets. I like the ones you can wrap all the way round you. (Bank of English)

Barry Richards and Viv Richards took similar risks but that sort of stroke is beyond the range of most players, even good ones. (Bank of English)

Introduction
Using one/ones for nouns
Using so as a complement substitute
Using do so as a substitute
Using so and not as clausal substitutes