Final answer:
The 1st person singular pronouns include 'I' in the subjective case, 'me' in the objective case, and 'my/mine' in the possessive case, each serving different grammatical functions.
Step-by-step explanation:
The 1st person singular pronouns include subjective case pronoun 'I', objective case pronoun 'me', and possessive case pronouns 'my/mine'. All three cases serve different functions in sentences. The subjective case, 'I', functions as the subject of a sentence, like in 'Antonio and I share an apartment downtown.'
The objective case, 'me', functions as the object of a sentence or preposition, as in 'She gave me a gift.' Finally, the possessive case pronouns 'my and mine' indicate ownership, such as in 'This is my book' or 'The ideas presented were mine.' Understanding the correct usage of these pronouns is essential in mastering the English language.