Site:mydomain.com - 4 results with different filenames

[candyoff]

Dear all

When I type
Site:mydomain.com in google.
It will have 4 results
1st, [mydomain.com...]
2nd, [mydomain.com...]
3rd, [mydomain.com...]
4rd, [mydomain.com...]

Why is that?
I thought it should only have one result with a sub link?

e.g [mydomain.com...]
¦
------ [mydomain.com...]