I open the book.

What is the book?

Open.

I am opening the book.

What is the book?

Open.

I opened the book.

What is the book?

Open.

I close the book.

What is the book?

Closed.

I am closing the book.

What is the book?

Closed.

I closed the book.

What is the book?

Closed.

To open is to give a present and a future. To close is to leave behind in the past.