  The Winograd Schema Challenge is both a commonsense reasoning and natural
language understanding challenge, introduced as an alternative to the Turing
test. A Winograd schema is a pair of sentences differing in one or two words
with a highly ambiguous pronoun, resolved differently in the two sentences,
that appears to require commonsense knowledge to be resolved correctly. The
examples were designed to be easily solvable by humans but difficult for
machines, in principle requiring a deep understanding of the content of the
text and the situation it describes. This paper reviews existing Winograd
Schema Challenge benchmark datasets and approaches that have been published
since its introduction.
