Like= 'similar to', 'the same as'. Note that you cannot use as in this way:
·What a beautiful house! It's like a palace. (not 'as a palace')
·'What does Sandra do?' 'She's a teacher, like me.' (not 'as me')
·Be careful! The floor has been polished. It's like walking on ice. (not 'as walking')
In these sentences, like is a preposition. So it is followed by a noun (like a palace), a pronoun (like me/ like this) or -ing (like walking)
You can also say 'like (somebody/ something) doing something':
·'What's that noise?' 'It sounds like a baby crying.'
Sometimes like= 'for example':
·Some sports, like motor racing, can be dangerous.
You can also use such as(=for example):
·Some sports, such as motor racing, can be dangerous.
We use as (not 'like') before a subject+verb:
·I didn't move anything. I left everything as I found it.
·They did as they promised. (=They did what they promised)
Compare like and as in these sentences:
·You should have done it like this. (like+pronoun)
·You should have done it as I showed you. (as+subject+verb)
We also say as you know/ as I said/ as she expected/ as I thought etc.:
·As you know, it's Tom's birthday next week. (=you know this already)
·Jane failed her driving test, as she expected. (=she expected this before)
Note that we say as usual/ as always:
·You're late as usual.
As (preposition)='in the position of', 'in the form of' etc.:
·A few years ago I worked as a bus driver. (not 'like a bus driver')
·We've got a garage but we haven't got a car, so we use the garage as a workshop.
·Many English words (for example, 'work' and 'rain') can be used as verbs or nouns.
·London is all right as a place to visit, but I wouldn't like to live there.
·The news of her death came as a great shock.
We say regard...as:
·I regard her as my best friend.