Answer: "On" and "for."
Step-by-step explanation: A preposition is a word governing, and usually preceding, a noun or pronoun and expressing a relation to another word or element in the clause. In English, some examples of prepositions are of, with, at, from, until, against, despite, towards, between, around, for, in, on, etc. In the given sentence, we can see two examples of prepositions: "on" in the phrase "on the table" and "for" in the phrase "for our teacher."