We can't know for sure because this is not a controlled experiment.

我们不能确定，因为这不是一个可控实验。

youdao

DESIGN: a controlled experiment was conducted on the basis of clinical diagnosis.

设计：以诊断为依据设立对照的实验研究。

youdao

DESIGN: a controlled experiment was conducted on the basis of clinical diagnosis.

设计：以诊断为依据设立对照的实验研究。

youdao