Prepositions are words such as aboard, above, across, after, along, anti, around, as, at, before, beneath, below, behind, beside, by, but, beyond, between, concerning, considering, down, during, except, for, following, like, inside, into, minus, near, off, on, onto, plus, through, to, under, up, upon, with, withought and many more!! in your sentence the prepositions would be on, now, and for that i know of but there could be more!! Hope this helps!!!:)
There are quite a few English words that contain letters that are not suppose to be said including: debt and write. These left out letters can often tell us about the history and origin of the word and some places in the world has these which can tell us about who lived there at the time. This is called etymology.