Grammar - ing endings

Gerund

The continuous form of a verb ends in -ing and is formed using past, present, future or conditional forms of the verb 'to be', e.g. was, is, will be, would, etc.

He is painting.
She was waiting.
They will be coming.
We would be staying.
I would have been leaving.

A gerund functions as a noun and is used alone

Being a parent is not always easy.
Swimming is good exercise.