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: Then, on December 21, 1994 the volcano spewed gas and ash which was carried as far as 25 km (16 mi) away by prevailing winds.

On 12/21/1994, the volcano shot out gas and ash that traveled up to 16 miles away.