When people say “they're engaged,” the phrase “to be married” 'is understood'. [=“they're engaged” is understood to mean “they're engaged to be married”]
We still don't fully 'understand' the causes of the disease. = The causes of the disease are still not fully 'understood'.
He believed it 'was understood' [=believed that everyone had agreed] that he would be paid for the work.
(..) Wait a second. On a real world op, we always use back-ups. Two is one, one is none. - Is that understood? - Yeah! O'Neil to C.O. Office. O'Neil, the C.O. Wants you in his office. - Hey. (..)1997 G.I. Jane
(..) more detail in your reports. Let's include more background information. Past training reps; medical history; any grievances she previously filed. Understood? Um, actually, not completely, sir. Am... Am I being asked to provide ammunition against this woman... in case the outcome isn't (..)1997 G.I. Jane