Randomly chosen control subjects were frequency-matched for age, race, and geographic study location.

他们还随机选取了年龄、种族和所在地区都相符的对照样本。

youdao

Randomly chosen control subjects were frequency-matched for age, race, and geographic study location.

他们还随机选取了年龄、种族和所在地区都相符的对照样本。

youdao