The seasons keep changing because the tilt of the Earth's axis never changes while the earth circles the sun.
(The seasons; keep changing; because the tilt of the Earth's axis never changes) (the tilt of the Earth's axis; never changes; T:while the earth circles the sun) (the earth; circles; the sun)
The seasons the tilt of the Earth's axis the earth
keep changing never changes circles
because the tilt of the Earth's axis never changes
T:while the earth circles the sun
the sun