Before revision: He proposed that fixed and broad information would be represented as the frame, but it would also be composed of slots that would accept a range of values; but if the world didn't have a value for a slot, then it would be filled by a default value.
After revision: He proposed that fixed and broad information would be represented as the frame, but it would also be composed of slots that would accept a range of values; but if the world did not have a value for a slot, then it would be filled by a default value.