The "ing" form: as a noun, verb, adjective, subject, object, adverb, or clause

People learning English find the various ways that words end with "ing" to be tricky.  In certain sentences the distinction can be arbitrary.  This entry has two parts:  summary examples followed by external references to detailed information.

Here is a quick summary / example table of the "ing" forms that are possible:

Type	Explanation	Example
Gerunds	The gerund is a non-finite verb form that can function as a noun. The English gerund ends in "-ing."  These nouns are nearly always uncount nouns (you can use the search field on this page to research uncount nouns further).	I love playing tennis.
An object		I love playing tennis. I like swimming. I saw a cat chasing a mouse.
An indirect object		I never gave studying all of my attention.
An adverbial		You can ruin your health by smoking often. There were many people jumping on the car.
As a clause		I heard someone saying that.
As the subject of a verb		Learning English is easy.
As the subject of a sentence		Learning is easy.
As the object of a verb		We love learning English.
As an adjective		I saw the flying aircraft.
	* believe it or not, there are more forms--check out the resources, below.

Here are some resources that explain the "ing" form in detail:

• English Grammar Secrets - "ing forms"
• British Council - "ing forms"
• Wikipedia - the "gerund"