posted by Writeacher .
Scroll down to the sections on Action Verbs and Linking Verbs. The explanations are really good and there are LOTS of examples to help you understand each term better.
Predicate nouns and adjectives are just what comes on the "other side" of a linking verb. If it's a pred noun, it'll be the same as the subject; if it's a pred adjective, it'll be describing the subject.
Scroll or look down a bit and find the explanation and examples of these two functions of nouns and adjectives.
Here's another with good explanation and examples -- and a little quiz you can test yourself with.
Please repost if you have further questions.