I find it helpful when I can recognize what construction / parts of speech unfamiliar words (or clauses) belong to. That is, if I recognize a grammatical construction, I feel like I have a good chance of later understanding the sentence.
I have no guesses about what constructions / tenses etc are used to create "offerts à gagner" in the following sentence that I see on my McDonald's take-out bag:
20 forfaits vacances « Grande aventure canadienne » offerts à gagner dans le cadre du jeu!
(20 “Great Canadian Adventure” Trips available to be won in the Game!)
(To be fair, I don't know what grammar is used in the English "available to be won", either.) I understand "20 Great Canadian Adventure Trips" is acting as a subject, but I don't understand what grammar constructs "available to be won".
My guesses don't illuminate. My first guess is that it kind of sounds like the passive voice, but when I look up passive voice constructions in French, none of them match "offerts à gagner". My second thought is "I don't know where the verb is; that is, the verb that follows the [subject] [verb] construction". "Available" sounds like an adjective or an adverb. "20 Trips [are] to be won" – is that the basic sentence? I'm not sure.