Page 163 - Advanced English Grammar in Use

O n e a n d o n e s ( T h e r e ' s m y c a r - t h e g r e e n o n e . )

We can use one instead of repeating a singular countable noun when it is clear from the context
what we are talking about:
• 'Can I get you a drink?' 'It's okay, I've already got one (= a drink).'
• 'Is this your umbrella?' 'No, mine's the big blue one (= umbrella).'
Ones can be used instead of repeating a plural noun:
• I think his best poems are his early ones (= poems).
• People who smoke aren't the only ones (= people) affected by lung cancer.
We don't use one/ones instead of an uncountable noun:
• If you need any more paper, I'll bring you some, (not ...one/ones.)
• I asked him to get apple juice, but he got orange, (not ...orange one/ones.)
Notice that we can't use ones without additional information (e.g. small ones, ones with blue
laces). Instead, we use some. Compare:
• We need new curtains. Okay, let's buy green ones this time. / ...ones with flowers on. and
• We need new curtains. Okay, let's buy some, (not ...let's buy ones.)

We don't use one/ones:
• after a - instead we leave out a:
• Have we got any lemons? I need one for a meal I'm cooking, (not ...need a one...)
• after nouns used as adjectives:
• I thought I'd put the keys in my trouser pocket, but in fact they were in my jacket pocket.
(not ...my jacket one.)
Instead of using one/ones after personal pronouns (my, your, her, etc.) we prefer mine, yours,
hers, etc. However, a personal pronoun + one/ones is often heard in informal speech:
• I'd really like a watch like yours, (or '...like your one.' in informal speech)
We can leave out one/ones:
• after which:
• When we buy medicines, we have no way of knowing which (ones) contain sugar.
• after superlatives:
• Look at that pumpkin! It's the biggest (one) I've seen this year.
• If you buy a new car, remember that the most economical (ones) are often the smallest.
• after this, that, these, and those:
• The last test I did was quite easy, but some parts of this (one) are really difficult.
• Help yourself to grapes. These (ones) are the sweetest, but those (ones) taste best.
(Note that some people think 'those ones' is incorrect, particularly in formal English.)
• after either, neither, another, each, the first/second/last, etc. (the forms without one/ones are
more formal):
• Karl pointed to the paintings and said I could take either (one), (or ...either of them.)
• She cleared away the cups, washed each (one) thoroughly, and put them on the shelf.
We don't leave out one/ones:
• after the, the only, the main, and every:
• When you cook clams you shouldn't eat the ones that don't open.
• After I got the glasses home, I found that every one was broken.
• after adjectives:
• My shoes were so uncomfortable that I had to go out today and buy some new ones.
However, after colour adjectives we can often leave out one/ones in answers:
• 'Have you decided which jumper to buy?' 'Yes, I think I'll take the blue (one).'
A/an and one => IffHETH