Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: Atlantic hurricane seasons Pre-1600 1600s / 10s 1620s / 30s Observation data for years before 1492 is completely unavailable because record keeping was virtually non-existent in the pre-Columbian era, and any records that may have once existed have long since been lost.

Atlantic hurricane seasons: Pre-1600 1600s / 10s 1620s / 30s: Observation data for years before 1492 is not available because record keeping was virtually non-existent in the pre-Columbian era. Any records that may have existed have long since been lost.