This app was removed from the App Store.
English Grammar Prepositions Test
iOS Universal Education
Prepositions are short words (on, in, to) that usually stand in front of nouns (sometimes also in front of gerund verbs).
Even advanced learners of English find prepositions difficult, as a 1:1 translation is usually not possible.
There are hardly any rules as to when to use which preposition. The only way to learn prepositions is looking them up in a dictionary, reading a lot in English (literature) and learning useful phrases off by heart (study tips).
And check your skill with this app.