0 used to refer to a person, object, idea, etc. that is separated from the speaker by space or time: --
1 used to introduce a clause that reports something or gives further information, although it can often be left out: --
2 used as the subject or object of a verb to show which person or thing you are referring to, or to add information about a person or thing just mentioned. It is used for both people and things. It can often be left out: --
3 used to make a connection with an earlier statement: --
4 as much as suggested: --
5 used to refer to a person, object, event, etc., separated from the speaker by distance or time, or to something that has been referred to before, or to point to a particular thing: --
I should be there by seven, that is, unless there’s a lot of traffic.
She called him an imbecile, and at that (= immediately after that) he stormed out of the room.
If she could play like that (= the way she is now playing) every day, she’d be a star.
Put that box (= the particular box referred to) down before you drop it.
This peach isn’t ripe – can I have that one (= the one farther away) on the table?
We haven't got that much time.
I can't really eat that much.
Charles had told her off. That's why she was so upset.
The yogurt that you bought was really nice - where did you get it?
The work that the students do during the year will count towards their final degrees.