In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

Q: The Lower Cretaceous is the first geological epoch in the Cretaceous .

A: The Early Cretaceous ( geochronological name ) or the Lower Cretaceous ( chronostratigraphic name ) , is the earlier or lower of the two major divisions of the Cretaceous .
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Q: When rainbands near frontal zones get close to steep mountains , a low-level barrier jet stream forms parallel to and just before the mountain ridge .

A: When bands of precipitation near frontal zones approach steep topography , a low-level barrier jet stream forms parallel to and just prior to the mountain ridge , which slows down the frontal rainband just prior to the mountain barrier .
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Q: The Airbus A318 is a European airliner designed and built from the Airbus A319 .

A:
The Airbus A318 is the smallest member of the Airbus A320 family of short- to medium-range , narrow-body , commercial passenger twin-engine jet airliners manufactured by Airbus .
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