When to use "de" before verbs

When to use "de" before verbs
 

Just reading something here, and came across the sentence: "emocionado de trabajar con Tim". I also noticed it here: "No tuvimos oportunidad de ver el fantástico espectáculo."

Why is this necessary and when do I need to use de?

Cheers for the help!!

"De" allows you to parse the sentence properly

emocionado trabajar = emotional working ...
emocionado de trabajar = thrilled of working ...

Even months later, I'm still having trouble with this issue. I was wondering if you or anyone else could clarify a bit for me. For example, if I want to say "This year's survey of farmers should have wrapped up" could i translate the meaning to "La encuesta de los granjeros de este año debe haber terminado" or would the ending be "debe haber de terminado"? Sometimes when I see 3 verbs chunked together (consecutively in english) I notice that between the second and third verb the word "de" is thown in there. is there a general rule i can use for when to use de and when not to? thanks!

In the 'deber de' construct, the preposition 'de' is used to express likelihood. The verb (deber) is conjugated. The preposition follows the conjugated verb. What follows 'de' is always a noun, even though it may look like a verb to you. An infinitive functions as a noun in Spanish.

So 'debe de haber terminado' is correct. The conjugated verb and its preposition are back-to-back. The infinitive 'haber terminado' acts as a noun.

Without "de" it also expresses conjecture in many regions: "ya debe haber terminado".

I think Tycholiz' question is too generic. We have adjectives followed by nouns -including infinitives-, we have some constructions involving verbs and nouns, as this "(deber) de ...", and we also have verbs followed by nouns:

cansado de esperar (adjective followed by noun) -de denotes reason-
cansado de esperar pero contento de poder estar haciéndolo ("poder estar haciéndolo" is a extremely complicated noun constructed by verboides and a pronoun)

vengo de trabajar (verb followed by noun) - de denotes origin-
vengo de trabajar y voy a pasear ( ir+a being a verbal periphasis)