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.
One example: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution is here: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Now, solve this: Race length can be either a time or a number of laps .
Solution:
Race length can be determined by a number of laps or total time , in which case the number of remaining laps is calculated as the race progresses .