双刃大刀

例句：

1. 1. He used to be a skilled blacksmith, but now he's become a double-edged sword.
   他以前是个熟练的铁匠，但现在他成了一把双刃剑。
2. 2. The situation is tricky;we need both sides to cooperate.
   情况棘手，我们需要双方合作。
3. 3. This policy has both advantages and disadvantages.
   这项政策既有优点也有缺点。