- It's like a mansion(not as a mansion)
- He's a doctor, like me(not as me)
- It's like surfing on the snow(not as surfing)
In these sentences, like is a preposition, it is followed by a noun(like a mansion), a pronoun (like me) or -ing(like surfing). We can also use like when somebody/something is doing something:
- What's that sound? It sounds like someone crying.
As = we use it before a subject+verb:
- The place have changed a bit, everything is as I left.
- He did as he promised.
Compare: like and as.
- Look. It has to be done like this.(like + pronoun)
- Look. It has to be done as I told you.(as + subject + verb)
We also say: as usual, as always.
Take a look at it:
- During the F1 the streets was used as a parking.(it really was a parking)
- There are some car parked near by, the street is like a parking(it isn't really a parking)
Mark is the direcito. As the director, he has many things to intend to.(As the director: in his position as a the director)
George is the assistant director. Like the director (Mark), he also has many things to be in charge of.(Like the director: similar to the director)
It was not that hard, wasn't it?