had to be, ought to be, might have been; which, when, where It is not known when ancient civilizations found out how to use the cacao's seeds. It____ by accident ____ the beans fell into a fire and roasted, releasing a chocolate-like smell.
had to be, ought to be, might have been; which, when, where It is not known when ancient civilizations found out how to use the cacao's seeds. It____ by accident ____ the beans fell into a fire and roasted, releasing a chocolate-like smell.
