Verb+ -ing form
I enjoy working on the emergency ward.
Verb+infinitive or -ing form but different meanings
I tried giving up chocolate= It was no problem stop eating it
I tried to give up chocolate=Couldn´t stop eating.
He remembered sending a card=he remebers sending the card.
He remembered to send the card=he remembered he needs to send the card.
See, watch, hear, feel, etc can be used with object + -ing form to talk about an action that is in progress:
He saw them crossing the street=they were crossing the street when he saw them