Past Perfect Simple / Continuous

No one had SEEN / SEEING inside the tomb for 3000 years.

It was obvious he'd failed the exam. He HADN'T EVEN OPENED / HADN'T EVEN BEEN OPENING his text book.

Had Schliemann LOOKED / BEEN LOOKING for Troy a long time when he found it?

I HAD BEEN THINKING / HAD THOUGHT about you when the phone rang.

HAD THEY INTERVIEWED / HAD THEY BEEN INTERVIEWING the archeologist before?

Oscar Wild HAD LIVED / HAD BEEN LIVING in Paris when he died.