  This study is to review the approaches used for measuring sentences
similarity. Measuring similarity between natural language sentences is a
crucial task for many Natural Language Processing applications such as text
classification, information retrieval, question answering, and plagiarism
detection. This survey classifies approaches of calculating sentences
similarity based on the adopted methodology into three categories. Word-to-word
based, structure based, and vector-based are the most widely used approaches to
find sentences similarity. Each approach measures relatedness between short
texts based on a specific perspective. In addition, datasets that are mostly
used as benchmarks for evaluating techniques in this field are introduced to
provide a complete view on this issue. The approaches that combine more than
one perspective give better results. Moreover, structure based similarity that
measures similarity between sentences structures needs more investigation.
