Polite questions and non-defining relative clauses
1.) Non-defining relative clauses give additional information about a person or thing.
David, who comes from UK, is a very intelegent.
WE USE WHO FOR PEOPLE
WE USE WHICH FOR THINGS
THAT = WHICH= WHO
2.) Polite questions
Sometimes direct questions don't sound polite.
Direct: What's it about?
Polite: Do you know what is it about?
Make polite questions
1.) I wonder if... ( tell me the time)?
2.) Can you tell me...( where/High Street)?
3.) Do you know...( what/our homework)?