varies是什么意思？

The amount of sleep that each person needs varies.

The sleep a person needs varies from day to day

Even if they could, Simpli Safe claims that its system is always evolving, and that it varies slightly from system to system, which means there wouldn't be a universal magic formula for cracking it.

Everybody sleeps, but what people stay up late to catch—or wake up early in order not to miss—varies by culture.

No one has a good answer" as to why fertility varies among countries, says sociologist Andrew Cherl in of The Johns Hopkins University.

This varies dramatically depending on crop, from three calories for plant crops to 35 calories in the production of beef

Even within the tropics, language diversity varies widely.