a mystery to (one)(redirected from a mystery to them)
a mystery to (one)
Something that is difficult to understand. Why she walked out in such a huff this morning is a mystery to me! She was acting normally before that. It was a mystery to scientists where the birds migrated to until they banded some of them and tracked their movement. A: "What caused this sinkhole? Do we have any idea yet?" B: "No, it's still a mystery to us."
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