what are gerunds.....plzz explain

gerunds are verb-nouns. they occur very often but are difficult to identify.

it is a non finite verb and infinitive.

as aditya said it ends mostly with -ing.

You can also refer to this from wiki-

In Latin and English grammar, the gerund is a non-finite verb form used to make a verb phrase that can serve in place of a noun phrase. The English gerund ends in -ing (as in I enjoy playing basketball); the same verb form also serves as the English present participle (which has an adjectival or adverbial function), and as a pure verbal noun. The gerund is the form that names the action of the verb (for instance, playing is the action of "to play"). It should not be confused with other nouns ending in -ing, such as building, painting, writing, which name the product resulting from an action.

The Latin gerund (gerundium) is a verb form which behaves similarly to a noun, although it can only appear in certain oblique cases. (It should not be confused with the Latin gerundive, which is similar in form, but has a passive, adjectival use.)

In relation to other languages, the term gerund may be applied to a form which has noun-like uses like the Latin and English gerunds, or in some cases to various other non-finite verb forms, such as adverbial participles.

Gerund comes from the Latin gerundium, which itself derives from the gerundive of the Latin verb gero, namely gerundus, meaning "(which is) to be carried out".

The following sentences illustrate some uses of gerund clauses, showing how such a clause serves as a noun within the larger sentence. In some cases the clause consists of just the gerund (although in many such cases the word could equally be analyzed as a pure verbal noun).

• Swimming is fun. (gerund as subject of the sentence)
• I like swimming. (gerund as direct object)
• I never gave swimming all that much effort. (gerund as indirect object)
• Eating biscuits in front of the television is one way to relax. (gerund clause as subject)
• Do you fancy going out? (gerund clause as direct object)
• On being elected president, he moved with his family to the capital. (gerund clause as complement of a preposition)

Using gerunds of the appropriate auxiliary verbs, one can form gerund clauses that express perfect aspect and passive voice:

• Being deceived can make someone feel angry. (passive)
• Having read the book once before makes me more prepared. (perfect)
• He is ashamed of having been gambling all night. (perfect progressive aspect)

For more detail on when it is appropriate to use a gerund, see Verb patterns with the gerund below, and also Uses of English verb forms: Gerund.