To avoid common grammar mistakes, you must understand how each pronoun changes its form when it moves from the subject position (before the verb) to the object position (after the verb).

The Biggest Grammar Trap: Many English learners say things like “Me and my friend went to the park.” This is wrong because it is before the verb went (subject position). The correct form is: “My friend and I went to the park.” Save “me” for the end!