semantic of prepositionscan you tell me the most important on the subject of semantic of prepositions?
Prepositions are metaphorical in nature and vary in different languages. For example, we speak of being "in love," as though love were a container we have put ourselves in. In some languages, to show possession, someone will say "the book is on me," thus using a metaphorical proximity to show one owns something. Writers like George Lakeoff and Zoltan Kovecses have wonderful and interesting things to say about prepositions.
People use different prepositions based on where they live. For example, in California we wait "in line" but in other places in the country you wait "on line" and in some places you "que" instead. Thus meanings can be very regional.
I know prepositions are quite tricky in Latin, because they're implied by the ablative (not always, but often). So if you said, "Laborat agro," that could mean "he labours in the field, by the field, on the field, etc." And then you would have to choose the one which makes most sense in the sentence, given the context. So, I'd say the most important part of prepositions is to make sure they make sense within the context.