The present participle (also known as -ing, present continuous tense and gerund) is a kind of participle, which can be divided into present participle and past participle, both of which are non-finite verbs. Now participles can not act as predicates alone in sentences, but as other components (attributive, predicative, complement and adverbial), and they have the nature of verbs, so they are also a kind of quasi-verbs. General formula: do; Generally passive: doing it; Perfect: completed; Completely passive: Completed. All negative forms begin with -ing plus not, including the independent nominative form.