  Sluice resolution is a problem where a system needs to output the
corresponding antecedents of wh-ellipses. The antecedents are elided contents
behind the wh-words but are implicitly referred to using contexts. Previous
work frames sluice resolution as question answering where this setting
outperforms all its preceding works by large margins. Ellipsis and questions
are referentially dependent expressions (anaphoras) and retrieving the
corresponding antecedents are like answering questions to output pieces of
clarifying information. However, the task is not fully solved. Therefore, we
want to further investigate what makes sluice resolution differ to question
answering and fill in the error gaps. We also present some results using recent
state-of-the-art question answering systems which improve the previous work
(86.01 to 90.39 F1).
