sign of pericardial effusion

例句：

1. 1. The sudden drop in the stock price was a clear sign of trouble ahead.
   股票价格的突然下跌是前方有麻烦的明显迹象。
2. 2. The new policy is a clear sign that the government is committed to environmental protection.
   新政策是政府致力于环境保护的明确信号。
3. 3. The rising sun was a clear sign that spring had arrived.
   升起的太阳是春天到来的明确信号。