What’s the name of the village where you got married? Defining – where cannot be omitted

She told me that Vasilis had failed his driving test, which didn’t surprise me at all. Non-defining – which refers to the whole clause

That song always reminds me of the time when I was working in Brazil. Defining – when can be omitted

Lady Gaga, whose real name is Stefani Joanne Angelina Germanotta, was born on March 28 1986. Non-defining

Emma received a phone call from her Managing Director, who had been impressed by her sales performance. Non-defining – she has, we assume, only one Managing Dir

He hasn’t given me back the book that I lent him. Defining – that can be omitted

Defining – which cannot be omitted as it follows a preposition. The sentence could be changed to: Few written records have survived so it is a period of history

He’s the only person in this class whose first name begins with ‘Z’. Defining – whose cannot be omitted