If a piece of knitted or woven cloth, a knot, or a mass of thread unravels, it separates into a single thread, and if you unravel it, you separate it into a single thread.

You'd better mend that hole before the whole sweater starts to unravel. 你最好把那个洞补上，免得整件毛衣脱线。

I had to unravel one of the sleeves because I realized I'd knitted it too small. 我不得不拆掉一只袖子，因为我发现它织得太小了。

If you unravel a mysterious, unknown, or complicated subject, you make it known or understood, and if it unravels, it becomes known or understood.

We have a long way to go before we unravel the secrets of genetics. 在揭开遗传学之谜前，我们还有很长的路要走。

If a process or achievement that was slow and complicated unravels or is unravelled, it is destroyed.

As talks between the leaders broke down, several months of careful diplomacy were unravelled. 由于领导人之间的会谈破裂，几个月精心策划的外交努力付诸东流。