1 sentence for 一定 (yī​dìng — fixed)

1. 您的身体每天需要一定数量的卡路里。

   nín de shēn​tǐ měi​tiān xū​yào yī​dìng shù​liàng de kǎ​lù​lǐ.

   Your body needs a certain number of calories every day.

   Source: CCMatrix