I often heard people say: "Es ist mir klar...." so the answer I gave here was: "Ist es Ihnen klar, dass Sie zwei verschiedene Schuhe tragen?" Is that incorrect?
I would leave out the "es", because the thing, which is "klar" or not, is mentioned in the subordinate clause.
Danke für die Erklärung!
Does any body know why are they using "ist" and not "sind"?
Literally "Ist Ihnen klar,..." would be "Is (it) clear to you,..."
I think there is an implied subject here. You could leave the sub-clause and change the sentence to: "Ist es (Ihnen) klar?"
Yes, the sub-clause is the subject, which the "es" would replace.
Could you say "Erkennen Sie . . . "?
That sounds philosophical. You wouldn't say that.
Thank you. I'll keep that in mind.