i can't put my finger on it

例句：
1.I can't put my finger on it,but I know I've seen you before.
我知道我曾经见过你,但记不起到底是在什么地方.
2.Something is wrong with this room,but I can't put my finger on what it is.
这房间有点不对劲,但我弄不清到底是啥不对劲.