thousands of (years) ago, fish were caught in nets and traps.

Ither a verb prepostion interjection, noun

Well, it looks as if you need to study the parts of speech in English. There are 8 categories: noun, verb, adjective, adverb, pronoun, conjunction, preposition, and interjection.

http://www.writingcentre.uottawa.ca/hypergrammar/partsp.html

http://www.ucalgary.ca/UofC/eduweb/grammar/index.htm
Click on Parts of Speech at the left.

http://www.171english.cn/html/grammar/

Let us know what you think.

i belive the right answer would be a perposition.

I know what they all mean i just cant seem to pick them out of a sentence

If you're asking about "years," it is not a preposition.

Here's a list of common prepositions.

http://www.englishclub.com/grammar/prepositions-list.htm

well okay i know its not a nouns cause its not a person place or thing and its not a verb so i am thinking that maybe its a interjection

i found out that its is a noun im alittle confused

Yes, it's a noun. Nouns are the names of people, places, things, or ideas. In a sense, "year" is an idea, and abstract concept -- humans have devised ways to measure time, and "year" is one of the measures. It's considered an abstract or an idea because it's not a person, a place, or a thing.

if im writng a sentence like (Daedalus and his son) were imprisioned in a great maze

Now Daedalus and his son would be the complete subject "were imprisioned" would be the complete predicate and "in the great maze" would be a prepositional phrase?

complete subject = correct

complete verb = "were imprisoned" (<~~watch the spelling)

prepositional phrase = "in a great maze" (yes)

complete predicate = "were imprisoned in a great maze"

complete verb would be verbal then?

The complete verb in this sentence contains the main verb (imprisoned) and its auxiliary or helping verb (is).

The word "verbal" is an adjective. To what type of verbal are you referring?