Ok. Airmanship 101:
If you hear a horn when you advance the thrust levers it is a T/O warning.
If you hear the horn in flight and you can cancel it with the ALT HORN CUTOUT button it is a pressurization warning!!!!!!!
If the letters under the selector say MAN and the blue light says MANUAL you are in MANUAL Mode.
If the letters under the bleed switch position say OFF then the bleed is OFF.
If the letters under the bleed switch position say ON then the bleed is ON.
If your ears sense something is unusual that is a cue to check the system.
If this is a problem for intrepid aviatiors then how on earth will they handle a fuel leak or hydraulic failure or even remember to retract the flaps after takeoff?