形容詞 unturned:

1. not turned

1. Of course, social science research is almost never conclusive. There are always methodological difficulties and stones left unturned.
   當然，社會科學的研究幾乎從來沒有結論?？偸怯蟹椒ㄉ系睦щy和人事未能盡到的情形。
2. The police left no stone unturned in their search for the missing child.
   警察為了尋找這個失蹤的兒童，使用了一要手段。