Non-defining relative clauses

Function:We use non-defining relative clauses to give extra information about the person or thing. It is not necessary information. We don’t need it to understand who or what is being referred to.

We always use a relative pronoun (who, which, whose or whom) to introduce a non-defining relative clause (In the examples, the relative clause is in bold, and the person or thing being referred to is underlined.)

Examples

1. Clare, who I work with, is doing the London marathon this year.
2. Not: Clare, I work with, is doing the London marathon this year.
3. Doctors use the testing kit for regular screening for lung and stomach cancers, which account for 70% of cancers treated in the western world.
4. Alice, who has worked in Brussels and London ever since leaving Edinburgh, will be starting a teaching course in the autumn.

Warning:

• We don’t use that to introduce a non-defining relative clause:
• Allen, who scored three goals in the first game, was the only player to perform well.
• Not: Allen, that scored three goals in the first game, was the only player to perform well.

Vocabulary  

Admission	Lighting
Charge	Row
Audience	Scenery
Costumes	Stage
Director	Venue

Defining relative clauses

Funcion: We use defining relative clauses to give essential information about someone or something – information that we need in order to understand what or who is being referred to. A defining relative clause usually comes immediately after the noun it describes.

We usually use a relative pronoun (e.g. who, that, which, whose and whom) to introduce a defining relative clause (In the examples, the relative clause is in bold, and the person or thing being referred to is underlined.):

·        They’re the people who want to buy our house.

·        Here are some cells which have been affected.

·        They should give the money to somebody who they think needs the treatment most.

·        [talking about an actress]

·        She’s now playing a woman whose son was killed in the First World War.

https://www.youtube.com/watch?v=mTwQz1e0Fgs