Final answer:
The student Nurzhan may refuse to eat potatoes for personal preferences, dietary restrictions, emotional reasons, or specific events.
Step-by-step explanation:
The student Nurzhan refuses to eat the potatoes at dinner for various possible reasons based on the provided texts.
In some cases, a character may refuse to eat potatoes due to personal preferences or dietary restrictions, as seen in the texts where the characters live without dining or eat only ginger-nuts.
In other cases, the refusal to eat potatoes may be due to an emotional state or a specific event, as seen in the texts where characters stare furtively at their wives or struggle with personal issues.