relative clause but omit which

[aysaa]

Hi,

-A clause is a group of words which contains a finite verb but (which) can't occour in isolation.

Is the relative pronoun 'which' coming after 'but' necessary, or is that understandable if omitted?

Thanks.

 

[emsr2d2]

Hi,

- A clause is a group of words which contains a finite verb but (which) can't [STRIKE]occour[/STRIKE] occur in isolation.

Is the relative pronoun 'which' coming after 'but' necessary, or is [STRIKE]that[/STRIKE] it understandable if omitted?

Thanks.

I prefer it with "which" but it would still be understandable without it.