What is practical preposition?
There is no such term as PRACTICAL PREPOSITIONS. However, you can study the topic 'PREPOSITIONS' in the link given below:
https://www.meritnation.com/cbse/class7/studymaterial/english/english-grammar/prepositions/30_443_1653#slide1_introduction-to-prepositions
https://www.meritnation.com/cbse/class7/studymaterial/english/english-grammar/prepositions/30_443_1653#slide1_introduction-to-prepositions