What happened next is mere guess work on my part, but I should say that Mrs. Inglethorp picked up the broken cup and placed it on the table by the bed. 
I can only make a guess as to what may have occurred next. 
mnli hypothesis: I can only make a guess as to what may have occurred next.  premise: What happened next is mere guess work on my part, but I should say that Mrs. Inglethorp picked up the broken cup and placed it on the table by the bed. 