A verb ending in -ing is either a present participle or a gerund. These two forms look identical. The difference is in their functions in a sentence.
A present participle is most commonly used as part of the continuous form of a verb, after verbs of perception, after verbs of movement, or as an adjective.
Present participles as part of the continuous form of a verb
Present participles are an element in all continuous verb forms (past, present, future, conditional, etc.). The helping verb will indicate the tense, while the present participle remains unchanging.
- He is painting.
- She was waiting.
- They will be coming.
- We would be staying.
- I would have been leaving.
Present participles after verbs of perception
Present participles can be used after verbs of perception in the pattern verb + object + present participle to indicate the action being perceived.
- We saw him swimming across the pond.
- I watched her painting Sarah's portrait.
- I couldn't hear her singing because of the noise.
- I would like to see you knitting sometime.
Present participles after verbs of movement, action, or position, to indicate parallel activity.
- She sat looking at the sea.
- He walks reading his newspaper.
- I cook listening to the radio.
- Sally lay listening to the bugs in the grass.
Present participles as adjectives
- Did you read that amazing book?
- This movie is so exciting!
- His economics class is boring.
Read more about using present participles.
The gerund always has the same function as a noun, although it looks like a verb. It can be used in the same way as a noun.
A gerund as the subject of the sentence
- Eating people is wrong.
- Driving too fast is dangerous.
- Walking is good for you.
- Your knitting is beautiful.
A gerund after prepositions
- Can you sneeze without opening your mouth?
- She is good at painting.
- I was the fastest at climbing the rope.
- He learns music by listening to the chords.
A gerund after certain specific verbs
- I like cooking.
- He enjoys walking.
- They hate milking cows.
- I can imagine drifting away in a balloon.
A gerund in compound nouns
- I took her to her driving lessons.
- We are going to the swimming pool.
- My uncle does a lot of bird-watching.
- I found this pie by dumpster-diving.
Read more about using gerunds.