Leigh Mumford, Thanks for solve my doubt! I would like have a lesson, but is a free lesson?

Thanks for helping! Now, I know the difference! :)

On is for a surface for prepositions of place - On the menu, on the wall, on the ceiling. For prepositions of time it is a specific time - on Friday, on the 13th I have a great lesson on prepositions. Why not book a class with me?

Hi Naif, I will try to help you with other ways to say the same words. that way you can make the connection. If you put the four words in the dictionary, it will become more clear. In = inside = within = enclosed On= over = on top of = above Examples: "I am in the building" "I put the book in the box" "It is raining so we stay in the house" "the book is on top of the table" "the car is on the road" "the hat is on my head"