like/ as

[LUPITA]

hello teachers,

when do you use "like" and when "as" I'm not sure of the rule...

eg. He works like a plumber.
he works as a plumber

eg. he is used as a modifier
he is used like a modifier


thanks in advance

lupita

[Tdol]

He works like a plumber = he isn't a plumber but works in a similar way (expensive and late )

He works as a plumber = he is one