Study these situations:
Joe was playing football. He hurt his knee.
You can say: Joe hurt his knee
playing football.
You were feeling tired. So you went to bed early.
You can say: Feeling tired, I went to bed early.

'Playing football' and 'feeling tired' are -ing clauses.
If the -ing clause is at the beginning of the sentence (as in the second example), we write a comma (,) after it.
When two things happen at the same time, you can use an -
ing clause:
- Kate is in the kitchen making coffee. (= she is in the kitchen and she is making coffee)
- A man ran out of the house shouting. (= he ran out of the house and he was shouting)
- Do something! Don't just stand there doing nothing!
We also use -
ing when one action happens during another action. We use -
ing for the longer action:
- Joe hurt his knee playing football. (= while he was playing)
- Did you cut yourself shaving? (= while you were shaving)
You can also use -
ing after
while or
when:
- Joe hurt his knee while playing football.
- Be careful when crossing the road. (= when you are crossing)
When one action happens before another action, we use
having (
done) for the first action:
- Having found a hotel, we looked for somewhere to have dinner.
- Having finished her work, she went home.
You can also say
after -
ing:
- After finishing her work, she went home.
If one short action follows another short action, you can use the simple -
ing form (
doing instead of
having done) for the first action:
- Taking a key out of his pocket, he opened the door.
These structures are used more in written English than in spoken English.
You can use an -ing clause to explain something, or to say why somebody does something.
The -
ing clause usually comes at the beginning of the sentence:
- Feeling tired, I went to bed early. (= because I felt tired)
- Being unemployed, he doesn't have much money. (= because he is unemployed)
- Not having a car, she finds it difficult to get around. (= because she doesn't have a car)
Use
having (
done) for something that happened before something else:
- Having already seen the film twice, I didn't want to see it again. (= because I had already seen it twice)
These structures are used more in written English than in spoken English.