for gerund or for continuous action

"Verb+ing" can be a gerund or a present participle. They look exactly the same (sorry!) but they function differently in a sentence. If a verb needs to be the subject or object of the sentence, we put it in gerund (+ing) form. A whole phrase that functions as a "thing" starts with a gerund. Gerunds also follow prepositions (there's one common exception, but that's a different topic). If you can replace "verb-ing" with a regular noun, then the "verb+ing" form is a gerund. Present participles are found in continuous tenses, they can work as adjectives, and they can introduce extra information about something. Quite flexible! Unlike gerunds, present participles cannot work alone - there is always another part of the sentence that it connects to. Well, that's the explanation. Have a look at these links for examples and exercises: http://grammar.about.com/od/basicsentencegrammar/a/verbalswhat.htm http://www.englishpractice.com/grammar/participles-gerunds-exercise/ http://lessons.englishgrammar101.com/EnglishGrammar101/Module3/Lesson3-11.aspx http://www.towson.edu/ows/exercises/Participles_Gerunds_Ex3.aspx

Also as a gerund e.g. I like doing. It's a fairly big topic though grammar books may not classify the issue in this way. Look up grammar books and study continuous tenses and the gerund. There may be other uses I have not thought of and a professional teacher will be able to help more.

When you're talking in the present continuos form :)