Many English adjectives are made from verbs by adding -ed or -ing. These are called participial adjectives. It is very common for learners to confuse them.
Here is the simple rule to remember the difference:
1. Adjectives ending in "-ed" describe feelings
We use -ed adjectives to describe how a person feels about something.
- I was very bored during the movie. (This is how I felt.)
- She is interested in history. (This is how she feels.)
- We were terrified of the storm.
2. Adjectives ending in "-ing" describe the cause
We use -ing adjectives to describe the thing, situation, or person that causes the feeling.
- The movie was very boring. (The movie caused the feeling of boredom.)
- History is an interesting subject. (History causes the feeling of interest.)
- The storm was terrifying.
Quick Check: Can a book be bored? No, because a book doesn't have feelings. A book is boring, which makes you feel bored.