Participial Adjectives

When talking about how someone feels, use an adjective with an -ed ending. When talking about the thing that gave you the feeling, use an -ing ending.
Such as:
I'm so bored in this class!
This teacher is too boring.

To watch a video explaining how these work:

https://www.youtube.com/watch?v=WtRCsmOWRXk

For more practice, click here:

http://web2.uvcs.uvic.ca/elc/studyzone/490/grammar/participial-adjectives1.htm 

http://www.learnenglishfeelgood.com/participle-adjectives2.html