1·He's been cudgeling his brain all day over this problem.
他整天都在为这个问题伤透脑筋。
2·He's been cudgeling his brains all day over this problem.
他整天都在为这个问题费脑筋。
3·The thoughts of our sage Confucius, however, were born through questions and replies with his disciples during their drifts in various kingdoms instead of cudgeling his brains in his study.
但我们的先哲孔子的思想不是在书斋里苦思苦想，而是在周游列国的颠沛中与弟子一问一答中产生的。