Since the simple gerund and the present participle have the same form (verb-ing), sometimes it can be difficult to decide whether an -ing form is a gerund or a present participle.
It may be worth remembering that a gerund always functions as a noun:
|Subject||Hiking can be a relaxing and rewarding activity.|
|Complement||What I really like is travelling to other countries.|
|Object of a verb||Jill suggested going for a drink.|
|Object of a preposition||He rushed out of the room without saying a word.|
|Object of a prepositional verb||Could you give up smoking?|
|Part of a compound noun||We had no drinking water left.|
The present participle has the following functions:
|Continuous aspect||I wasn’t listening.
What have you been doing?
You must be joking.
I happened to be passing your house.
|Adjective||The survey revealed some worrying results.
The results of the survey were/seemed worrying.
|Participle clauses||The man driving the car was not injured.
Tom lost his keys (while) walking through the park.
Opening the envelope, I found two concert tickets.
Having nothing left to do, Paula went home.
Sometimes it is a matter of interpretation whether an -ing form is a gerund or a present participle:
Hunting lions can be dangerous.
Hunting as a present participle functions as an adjective and describes lions. The sentence means:
Lions that hunt can be dangerous.
If hunting is a gerund, lions is its object and the sentence means:
It can be dangerous to hunt lions.