Learner chooses -ing when the noun performs the action and -ed when the noun receives it, in both participles and adjectives.
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Six sentences. Both forms exist; only one is true.
You find the subject dull. Which do you write?
The noun acts, the noun is acted on, and the pair everyone trips on.
the falling birth rate — it is falling
a surprising result — it surprises you
the increasing demand — demand is rising
Ask who is doing it. If the answer is the noun in front of you, use -ing.
One person, one machine, two roles.

Same person, same machine. The difference is who is turning whom.
Twelve nouns. Four take either, and mean different things.
Sort each item into the correct category
Ten sentences. Three could take either — the sentence decides.
I am very [bore] by this subject.
The results were [surprise] — nobody predicted them.
The [fall] birth rate has worried planners for a decade.
The [fall] tree blocked the road for two days.
[increase] demand has pushed rents up across the region.
The [increase] fees were announced by the university in March.
The [interest] students stayed behind to ask questions.
It was a [confuse] explanation and nobody followed it.
A [develop] economy still has most of its growth ahead of it.
The audience looked [confuse] by the end of the talk.
How something made you feel, and what the thing is like.
Think of something you read, watched or studied recently.
Sentence 1: how it made you feel. Sentence 2: what the thing itself is like.
The two sentences will use two forms of the same kind of word.
One per line.