as and like are used to make a comparison I swim like a fish (I am not I fish) I work as a doctor in a hospital (I am a doctor) Like your mother I have to tell you...... (I am not your mother) As your mother I have to tell you (I am your mother)

This is a very good website to answer your question. http://grammar.quickanddirtytips.com/like-versus-as.aspx

To continue with what Kemonia said, "like" can also be used to indicate how you feel about someone, such as I like your mother, meaning I am fond of her.