Issues #4 and #5 of Superman have dropped some serious hints that Lois Lane either knows or strongly suspects that Clark Kent is Superman. In issue #4 of Superman, Lois Lane busts Clark Kent for telling her that he was in Metropolis when he was actually in Smallville. Clark Kent apologizes and tells Lois Lane that he was visiting his parent’s grave. Lois Lane looks at a video on her computer of Superman flying away from a cemetery.

Do you think Lois Lane figured out that Clark Kent and Superman are one person

Anyone with a camera phone stands a damn good chance of finding out who Superman is these days.

I do. She's smart.

She seemingly almost discovered his secret identity in issue 5 or 6 when it was still written by Perez, but there was never a single mention of it afterwards. I personally don't think she knows, especially considering how Clark was distant to her during Action Comics 19 and 21 in terms of his identity.

Nope. If she did find out, it would be a bigger deal.

She's smart. I assume that she knows the secret Clark.