if an preposition is opaque , then sound will not rain through that preposition
downpour is not rain. locative_preposition is not spatial_preposition. opaque_covering is not opaque_thing. opaque_covering is opaque_thing. rain is pouring. preposition_of is preposition. preposition_of is not preposition. smoke is opaque_thing. smoke is not opaque_thing. downpour is rain.