If so, how had they kept it secret from human beings?

Devotion, labor and care couldn't be expected from human beings who saw no need for such things.

"The problem is that I feel isolated from other human beings."

"He has to be isolated from human beings in order to observe them."

This sense of being accepted comes in the first instance from other human beings.

These buildings had been constructed for a life form that must be very different from human beings.

If she was somehow different from other human beings, so what?

How can you fly from beings who are everywhere and see everything?

In my childhood I did not expect much from human beings.

Society has always to demand a little more from human beings than it will get in practice.