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.
eg：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.
eg：He’s not as tall as his brotherShe 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.
eg：He went to Cambridge University, as his father had before him.She’s a talented writer, as most of her family are.
In the following comparisons, like is a preposition and it’s followed by a noun or a pronoun.
eg：I’ve been working like a dog all afternoon.None of my brothers are much like me.She looks just like her mother.
Like and As if/As though
Like, as if and as though can all be used to make comparisons. There is no difference in meaning among the 3 forms.
eg：You look as if you’ve seen a ghost.You talk as though we’re never going to see each other again.It looks like it’s going to rain.
Expressions with ‘as’
The following expressions all use as.
eg：As you know, classes restart on January 15th.I tried using salt as you suggested but the stain still didn’t come out.As we agreed the company will be split 50/50 between us.Their house is the same as ours.