Complex sentence: The card you discarded just before the knock is still on top of the pile, so it is now available for you to take back if you want it-for example if you had just broken up a suit for tactical reasons you can now restore it.
Split into simpler sentences: The card you discarded just before the knock is still on top of the pile, so it is now available for you to take back if you want it. For example, if you had just broken up a suit for tactical reasons you can now restore it.