“I am boring,” a Japanese student a few years ago would tell me repeatedly. Actually, she was anything but. She meant she was bored.

Adjectives like boring and bored are often confusing to international students. They and many other English language-learners are confused by such participial modifiers — that is, adjectives that originate as participles. Such confusion is, across the board, one of the most common problems I encounter among students around the world, no matter what their native language.

What are participles? you may be asking. Even if you don’t know that grammatical term, you probably use them successfully all the time. They are the verb forms used with an auxiliary, or helper verb, to indicate the tense of the action. Participles come in present, the -ing form of the verb (Am I boring you? No, but you’re confusing me) and past. When you memorize a verb’s three basic forms — for example, regular verbs like walk, walked, walked or irregular ones like go, went, gone — the first is the base verb or simple present, the second simple past and the third the past participle.

When used as adjectives, participles follow a very simple rule: use the -ing form for what is performing the action and the -ed form for the recipient of the action. So a class, a book or a movie may be interesting or boring. You are interested or bored.

Some illustrations from J-school writing, the first from another Asian student:

I can see an endless number of outfit pictures and outfit combinations from Instagram and Pinterest and then I put the interested products and clothes on my online wish list.

No, the products aren’t interested; the writer is. The products are interesting.

Similarly, a student in the Spanish master’s program wrote:

One interested issued is that the total number of juveniles in court did not go up dramatically.

She, too, meant interesting.

That same student wrote in another story:

According to a statement given by Bellino in 2016 to Agencia Pública, a Brazilian publication specialized in investigative reporting, it was he who presented the Puerto Maravilla project to Trump.

No, Agencia Pública is a publication specializing in investigative reporting. A Brazilian student who wrote that she had worked in Japan for a newspaper specialized in Japanese Brazilians also meant specializing.

By now I may be boring you by repeating the same adjectives too many times, but the rule holds for just about any participle that makes sense as an adjective. (Not all do. Past participles of transitive verbs — the beaten path, the forgotten man — tend to work better as adjectives than intransitives like the bled wound. And some adjectives are derived from past participles rather than the participles themselves — for example, a shrunken head, even though the past participle of shrink is shrunk. But: a drunk driver.) As a Chinese student wrote:

I have come back very late this afternoon. It’s an exhausted trip!

No, he was exhausted; the trip was exhausting. And so is mastering English.