signal ambiguity

例句：

1. 1.The policeman signaled the driver to stop.
   警察示意司机停车。
2. 2. The new product has a clear signal of success.
   新产品有明显的成功迹象。
3. 3.The weather forecast indicated that it would be sunny tomorrow.
   天气预报表明明天会是晴天。