He crept around the room in the middle of the night.

The sound of the whistling arrow flying was a signal that the battle had begun.

I went to see the beautiful scenery of the Han River.

He is working as a member of the International Criminal Police Organization.

The Mariana Trench is the deepest part of the earth.

He is preparing his luggage for overseas travel.

Marbled meat is very delicious.

He turned right at the intersection.

He holds a very high position in that company.

What is the common difference of this arithmetic sequence?