Beats me! 问倒我了.
Search me. 这教我无从作答.
Who the hell knows? 鬼才晓得. This problem is not within my grasp. 这难题非我能力所及.
Got me. 难倒我了. I wonder myself. 我自己也想不通.
I honestly don't know. 说实在的,我不知道. It's a mystery to me 这对我来说, 是神秘难解之事.
