unravel

To undo or separate tangled threads; to investigate and solve a mystery; to begin to fail or fall apart.

• unravelling/ʌnˈrævəlɪŋ/(n)解开；瓦解

• unravel a mystery
• unravel a plan
• begin to unravel
• unravel the truth
• slowly unravel

1. 1.The detective spent months unravelling the complex web of financial fraud. (investigation)
2. 2.The alliance began to unravel when it emerged that both sides had been negotiating separately. (collapse)

• untangle/ʌnˈtæŋɡəl/— remove tangles from; clarify a confused situation
• disentangle/ˌdɪsɪnˈtæŋɡəl/— free from entanglement
• unpick/ʌnˈpɪk/— British; undo stitching; analyse in detail

from "un-" (reversal) + "ravel" = to entangle or disentangle (paradoxically, ravel once meant both)