This is because the temperature of the ground or groundwater a few feet beneath the earth&#146;s surface remains relatively constant throughout the year, even though the outdoor air temperature may fluctuate greatly with the change of seasons.
(This; is; the temperature of the ground or groundwater a few feet beneath the earth&#146) (s surface; remains; relatively constant; T:throughout the year)
This s surface
is remains
the temperature of the ground or groundwater a few feet beneath the earth&#146
relatively constant T:throughout the year