*Me alegro de que nosotros hayamos ayudado a organizar este evento.
Explanation:
To complete the sentence, they give us the verb that we must use, so we must identify the person in the sentence and the verb tense to be able to conjugate it in a logical way and that it has a relationship with what is being expressed.
I would say, depending on what level Spanish you’re in, writing a paragraph about a family or a night out at dinner would be easy and creative to write about
