Relative Clause

[majid]

Hello,

Could you please explain why 'The woman who is in the photo is my sister' can be reduced to 'The woman in the photo is my sister' but 'The woman who is a teacher is my sister' cannot be reduced to 'The woman, a teacher is my sister'. I need the grammar explanation. Thank you very much.

[James Trotta]

Grammatically speaking, you're missing a comma:

The woman, a teacher, is my sister.

That's fine grammar, but I doubt you'll ever need to use it in a conversation. Better would be:

My sister is a teacher.

[karlidoc]

When are you using a comma and when are you using a semi colon?

Thanks, karlidoc[

quote="James Trotta"]Grammatically speaking, you're missing a comma:

The woman, a teacher, is my sister.

That's fine grammar, but I doubt you'll ever need to use it in a conversation. Better would be:

My sister is a teacher.[/quote]