Task: Question Generation
Input (English): Context: " That 's why I thought you might be ill . " Sanzo 's frown deepened as he stared at the ground and ran a hand through his hair in distraction . " ... I ' m sorry , " he mumbled , shocking Hakkai and not paying attention at all to what he was saying as he retreated back inside .
Output (English): What may be the reason he retreated back insde ?