cannot put one's finger on 搞不懂，毫无头绪，一头雾水

　　Mike cannot put his finger on his girlfriend’s emotions.

　　Mike完全搞不懂她女朋友的情绪。

　　I still cannot put my finger on who wrote me that card

　　我还是不能确定那张贺年卡是谁寄来的。

　　疯狂练习吧！