which (ones)

[aysaa]

Hi,

1. There are lots of books here. Which (ones)are yours?

2. Which (ones) are long?

3. Which (ones) make the perfect partners?

Must we use 'ones' in these senteces or musn't?

Thanks.

 

[emsr2d2]

No. You can omit it.

 

[BobK]

:up: Or not. It's optional.

b