In the present- to give result of an action
The bomb exploded, destroying the building.
- to give the reason for an action
Knowing she loved reading, Richard bought her a book.
- to talk about an action that happened at the same time as another action
Standing in the queue, I realised I didn't have any money.
- to add information about the subject of the main clause
Starting in the new year, the new policy bans cars in the city centre.