Prepositions in Arabic are service words indicating the relation of a noun (as well as all parts of speech acting in its function) to other words in a sentence.

There are basic prepositions in Arabic:

1. مِنْ — expresses the starting point of the movement "from, from". For example: خَرَجَ مِنْ أَحْمَدُ الْمَدْرَسَةِ — "Ahmad was released from the school." 
2.إِلَى — expresses the direction to the object and means "at, to". For example: ذَهَبَ إِلَى أَحْمَدُ المَدْرَسَةِ — "Ahmad went to school." This preposition means the time limit "to". For example: حتتَّى الظُّهْرِ - "before noon".

3. في — being inside something both in the sense of place and in time "in". For example: فِي الْمَدْرَسَةِ — "in school."