What changes between “dakhala al-waladu yaḍḥaku” and “dakhala al-waladu wa-huwa yaḍḥaku”?

Supplementary Practice 6: Rhetorical Dialogue, Responding to Objections and Choosing the Right Expression

• The imperfect becomes negative
• The imperfect becomes past
• Huwa makes the second circumstantial expression nominal in its outer structure
• Both directly prefix circumstantial wāw to a bare affirmative imperfect