In the following examples, I'm not looking for what is "socially accepted" or "standard use" so much as I am just curious about the precise, grammatically correct answers. Take a sentence like "We went to the store." The subject is "we." However, we also frequently hear sentences like "All of us went to the store." Does using "of" turn an object pronoun into a subject pronoun? Or are we just accustomed to bad grammar? Another example: "They all bought candy," vs "All of them bought candy." "All of they bought candy," just sounds awkward, and I don't expect anybody would use it. But is "All of them bought candy," despite being common structure, grammatically correct as a sentence? Or should "They all bought candy" always be the preferred syntax?