In the midst of the heated debate, the ______ speaker eloquently argued his point, leaving the audience _______ of his rhetorical skills.

Explanation: The speaker **eloquently argued** his point, suggesting he spoke at length and well, and the effect was leaving the audience impressed. **Loquacious** means talkative or chatty, which fits 'eloquently argued his point.' **Astounded** means shocked or greatly surprised, often implying being impressed, which fits the positive description of his rhetorical skills. **Loquacious... astounded** fits the context best.