Winter, Spring, Summer, and Autumn.

Do they follow each other in regular order?

They do; Spring follows Winter, Summer follows Spring, Autumn follows Summer, Winter follows Autumn, and Spring follows Winter again.

How often have we these seasons?

As often as the earth moves around the sun, which is once a year.

What change is produced on the earth by its turning over?

The change of day and night.

Where is it day?

It is day on that part of the earth which is turned towards the sun.

Where is it night?