Bhagavad Gita - Lesson 33 Questions

Q1) Whom did Lord Krishna speak the Bhagavad Gita before Arjuna. How long ago was that?

Q2) What does Apauruseya mean. Please explain?

Q3) Why did Lord Krishna gave the knowledge of Bhagavad Gita to Arjuna when He had already given it to the Sun God?

Q4) There are many editions of Bhagavad Gita available in the market. Whose Bhagavad Gita should we read?