Can you help me with this sentence?

Question

In the prepositional group: for over thirty years... What's over? It´s an adverb or a preposition? I really don´t know the category and function. Thank you for your help.

Answer 1

It qualifies thirty years as a preposition. (meaning above in degree or quantity).

Well confusing. Have a look at item 14 on this. http://dictionary.reference.com/browse/o...