You know what probably happened? Somebody must have stolen my credit card.
I have seen the above sentences from a textbook.
According to a textbook, "You know what probably happened?" implies "I think something probably happened." Is this right?
Also, in this case, nobody is 100% sure that somebody stole my credit card. Thus, I cannot say something like the following.
You know what would probably have happened? Somebody must have stolen my credit card.
"Would have <p.p.>" governs subjunctive usage about a past event, so this is improper. Am I right?