Are you going on holiday in August?
Is it August that you are going on holiday in?
A student broke the window.
It was a student who broke the window.
I met your sister.
It was your sister (that) I met.
You spoke to my husband.
It was my husband you spoke to.
The dog chased the cat.
It was the dog that chased the cat.
I’m singing.
It’s me who is singing.
Sheila hid the book under the mattress.
It was Sheila who / that hid the book under the mattress.
John stole a book from the library last week.
It was John who stole a book from the library last week.