He can't spend too much time arguing with you about this matter. He has otherfish to fry.
他不能用太多的时间和你辩论这件事,他另有要事。
《新英汉大辞典》
2
His only son was hurt in an accident and he told his wife he couldn't go to the hospital until later because he had otherfish to fry — a million-dollar deal he was closing.
Honey, they want me to run for Congress, but I said no. I have otherfish to fry - I need all my time for my business so I can retire when I reach 50 and we can move to Hawaii.