In Writing styles^x, Prepositions^x

Hi, 1. As a rule, what comes after a preposition must or should be a noun or any noun equivalent? 2. I saw a lesson content writing that is written like this without the regard for English article rules, is it OK? Is it a norm to employ this type of writing style for lesson content section...

Hi, 1. As a rule, what comes after a preposition must or should be a noun or any noun equivalent? 2. I saw a lesson content writing that is written like this without the regard for English article rules, is it OK? Is it a norm to employ this type of writing style for lesson content section...