It should be taken into account that both the gerund (G) and the present particle (PP) have two properties: G -nominal and verbal ones and PP - verbal and adjectival or adverbial characteristics. Nominal characteristics of G: I'm very tired of rowing. Verbal ones: The girl burst out crying bittely. Adverbial character of PP: He hated the sound of rain pattering on the roof. Verbal ones: Opening the door, she went out on to the terrace.

The present participle: This is most commonly used: as part of the continuous form of a verb, he is painting; she has been waiting after verbs of movement/position in the pattern: verb + present participle, She sat looking at the sea after verbs of perception in the pattern: verb + object + present participle, We saw him swimming as an adjective, e.g. amazing, worrying, exciting, boring The gerund: This always has the same function as a noun (although it looks like a verb), so it can be used: as the subject of the sentence: Eating people is wrong. after prepositions: Can you sneeze without opening your mouth? She is good at painting after certain verbs, e.g. like, hate, admit, imagine in compound nouns, e.g. a driving lesson, a swimming pool, bird-watching, train-spotting http://www.edufind.com/english/grammar/gerund_present_participle.php

gerund = "ing" form of the verb present participle = had been, has been and so on.. ^^

gerund = noun present participle = verb