'As' is tiny, but mighty.
You can use it in lots of different ways.
So let's have a look at four
of them together.
You can use 'as' - number one -
to compare two people or things.
'Tokyo is as big as Los Angeles.'
(more or less)
Number two: to describe somebody's job:
'I used to work as a waitress.'
(And no, I wasn't very good),
or to describe something's function:
'Did you know that you can
use olive oil as shampoo?'
Me neither!
Number three: to say that something
happened at the same time
as something else.
'You rang me just as i was texting you.'
Number four: to give a reason like 'because'.
'As the sun is shining today
I think i might go for some fresh air after this.'
And as you have hopefully been
learning something new, why don't
you practice one of these in the comments now?