talk about live; world
facts about ourselve and world, fixed routines, feelings, thoughts and senses, plots of books, films...., instructions, directions
describe new or temporary situations
things happening at the moment of speak, things happening around us, changing situations, "now, these days, at the moment", temporary routines
historical events, experience during a particular period of time
finished time periods, short events, long events, states, repeated events
(four years; on holiday)
describe background to past events
Relative clauses identify which person or thing we are talking about. They make it possible to give more information about the person or thing.
The boy has gone to the beach.
The boy who lives next door has gone to the beach.
The book is very good.
The book that I bought yesterday is very good.
There is a photo of the hotel.
There is a photo of the hotel where we stayed.