飘忽不定

例句：

1. 1. The stock market is notorious for its frequent fluctuations.
   股市以其频繁的波动而闻名。
2. 2. The temperature fluctuated throughout the day.
   温度在一天中波动不定。
3. 3. The company's profits fluctuated significantly over the past year.
   该公司过去一年的利润波动显著。