When to Use Continuous form vs Future form in English - Basic English Grammar

In this video, Alisha answers 5 questions. - Can you explain the difference between will/be going to and will be doing/be going to be doing. I would like to know when we use continuous forms instead of using simple future tense - Could you explain the difference between roughly, approximately, and nearly? - What tense—present or future—must follow a 'command' clause? - How do I know when to reduce "I have" to "I've" and when not to? Is there any rule? - Sometimes, someone says "opportunity" and I am confused about whether I should respond with "opportunity" or "chance." What is the difference between those words, and when is the right time to say them?