Gerund

A gerund is a verb that acts as a noun. Every gerund ends in -ing.

• At the time I began attending the University of Alaska.
• When will you finish playing these silly games?
• Enter without knocking!
• I am tired of sitting here.

It is used in some structures, for example: can't help, It's not worth, have difficulty/problem, there's no point in, be used to, go, it's no use/good, it's a waste of time/money.

• I can't stand listening to this loud music!
• It is certainly worth seeing.
• I had  problems understanding what he was saying.