  The broader goal of our research is to formulate answers to why and how
questions with respect to knowledge bases, such as AURA. One issue we face when
reasoning with many available knowledge bases is that at times needed
information is missing. Examples of this include partially missing information
about next sub-event, first sub-event, last sub-event, result of an event,
input to an event, destination of an event, and raw material involved in an
event. In many cases one can recover part of the missing knowledge through
reasoning. In this paper we give a formal definition about how such missing
information can be recovered and then give an ASP implementation of it. We then
discuss the implication of this with respect to answering why and how
questions.
