His shoes are the biggest.
I am trying to guess if I need the word "ones" in the third sentence.
Her shoes are big.
His shoes are bigger.
His shoes are the biggest (ones)
Thank you.
6 Answers
Tuscantory, Nila is a Spanish native and is looking for English verification to which I say you do not necessarily need the (ones) and personally I think it sounds better without unless you are pointing them out in a group.
Sus zapatos son grandes. Sus zapatos son mas grandes. Sus zapatos son los mas grandes.
I wanted to find big shoes but the biggest ones were very expensive.
Is it necessary to write "ones" here?
If you are in english " ones" is redundant and not needed,
you could also say that " his were the largest!
Her shoes are big.
His shoes are bigger.
His shoes are the biggest (ones)
Ones is not needed in the last example. It can be added if you want it but either way is grammatically correct. I would not add it to the sentence unless you are pointing out a pair of shoes amongst a group of them, otherwise I think it makes the sentence ackward.
You don't need the "ones" in English, no. What are his shoes? They are the biggest. That's fine as it is. 
