As and like are often confused since they are both used to compare actions or situations. There are, however, important differences.
We use as to talk about job or function.
I worked as a shop assistant for 2 years when I was a student.
He used his shoe as a hammer to hang the picture up.
In comparisons, the structure ‘as adjective as’ is often used.
He’s not as tall as his brother
She ran as fast as she could.
In the following comparisons as is a conjunction
it’s followed by a clause with a subject and a verb.
He went to Cambridge University, as his father had before him.
She’s a talented writer, as most of her family are.