quality:correction, stylistic:style_transfer, linguistic:translation, linguistic:voice_change
Proper versus improper

In descriptions of some languages, prepositions are divided into proper (or essential) and improper (or accidental). A preposition is called improper if it is some other part of speech being used in the same way as a preposition. Examples of simple and complex prepositions that have been so classified include prima di ("before") and davanti (a) ("in front of") in Italian, and ergo ("on account of") and causa ("for the sake of") in Latin. In reference to Ancient Greek, however, an improper preposition is one that cannot also serve as a prefix to a verb.