是因为老鼠食物摄取量由多种因素决定，包括食物味道如何，实验前老鼠的饥饿程度以及食物本身的油腻感和饱食感等等。

Because food intake can be driven by a variety of factors including how it tastes, how hungry the mice were beforehand and how 'sated' or full the food made them feel.

youdao

富裕和贫寒、光荣和默默无闻、权力和屈服、强壮和软弱、健康和疾并教养和无知、工作和闲暇、饱食和饥饿、道德和罪恶，都不过是较高或较低程度的自由罢了。

Wealth and poverty, health and disease, culture and ignorance, Labour and leisure, repletion and hunger, virtue and vice, are all only terms for greater or less degrees of freedom.

youdao

富裕和贫寒、光荣和默默无闻、权力和屈服、强壮和软弱、健康和疾并教养和无知、工作和闲暇、饱食和饥饿、道德和罪恶，都不过是较高或较低程度的自由罢了。

Wealth and poverty, health and disease, culture and ignorance, Labour and leisure, repletion and hunger, virtue and vice, are all only terms for greater or less degrees of freedom.

youdao