I am working on this auxlang, and came up with these preposition meanings:

• belongings, relatives, titles, origin, cause
  
• through, during, by (instrumental), passive agent
  
• towards, until, dative
  
• before, inside, by (deadline)
  
• after, outside, from (time) on
  
• for (benefactive), according to, comitative
  
• against, contrary to

Question: Are my prepositions not specific enough?

To make conjunctions you would take these prepositions and annex the two basic conjunctions (like Romance porque, perché, pourquoi, etc), a realis one and an irrealis one. What I am thinking of:

cause-irrealis Germany win WW2 : Europe be very different
"If Germany had won WW2, Europe would be very different"
or "If Germany wins WW2, Europe will be very different"

From that fictional Europe:
cause-realis Germany win WW2 : Europe be very different
"Europe is very different because Germany won WW2"

Concern: I feel like I'm making an abstract mess. I have to come up with weird translations for, example:

accordingto-realis grass be tall outside gate : nobody open it in a long time
"Judging from the fact that the grass is tall outside the gate, it seems like nobody has opened it in a long time"

accordingto-irrealis grass be tall outside gate : nobody open it in a long time
"If the grass gets tall/had got tall, it will/would seem like nobody has opened it in a long time"