uncertain rate

例句：

1. 1. The company's growth rate is uncertain due to the economic downturn.
   由于经济衰退，公司的增长率不确定。
2. 2. The scientist used a mathematical model to predict the uncertain rate of global warming.
   科学家使用数学模型预测全球变暖的不确定速率。
3. 3. The project team was tasked with developing an uncertain rate of progress towards completion.
   项目团队被指派开发完成进度的不确定速率。