control sample

例句：

1. 1. The research team collecteda variety of samples to control for potentialconfounding factors.
   研究团队收集了多种样本，以控制潜在的混杂因素。
2. 2.The scientist conducted a controlled experiment to studythe effects of temperature on plant growth.
   科学家进行了一个受控实验，以研究温度对植物生长的影响。
3. 3. The company is usinga controlled sample to evaluate the effectivenessof their new product.
   该公司正在使用受控样本来评估新产品的有效性。