Hello, fellas. This session is about objects of prepositions. They are objects following prepositions in prepositional phrases.
Common prepositions are:
about, above, across, after, against, along, among, around, at, before, behind, below, beneath, beside, besides, between, beyond, by, despite, down, during, for, from, in, into, like, near, of, off, on, out, over, since, through, throughout, till, to, toward(s), under, until, up, upon, with, within, without
(More on prepositions: https://englishtips4u.com/2011/09/17/engclass-prepositions/)
The object of a preposition is a noun, pronoun, gerund, or noun clause. Objects of prepositions are not the subject of a sentence.
1) The student comes to the library.
2) They studied together without you.
3) She is interested in learning English.
4) The teacher is thinking about what he can do to motivate her students.
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition
Deborah Phillips, Longman Complete Course for the TOEFL Test