(This posting includes a handout which you are welcome to use with your students.)
When students see an –ed at the end of a word, they tend to automatically assume it’s a verb, and this assumption can lead them to grammar mistakes.
(* mistakes—These sentences are missing a verb.)
*Kai embarrassed during his speech.
* Rumi interested in horses.
To help students in the most efficient manner, I will sometimes paint with a broad brush. So I simply tell my students that these words are adjectives: surprised, embarrassed, confused, interested and shocked. They need a verb with them.
(correct): Kai was (v) embarrassed (adj) during his speech.
Avoiding unnecessarily complicated information
It’s true that those words can be can be used as verbs, for example:
– It embarrassed (v) Kai that he forgot some of his speech.
But in all my years of teaching writing, I rarely see students use them that way. They almost always use them as adjectives, so I don’t waste their time/mental energy talking to them about using these as verbs. Instead, I just generalize and tell them that they are adjectives.