Question

 Bears _______ fat stores throughout the summer and fall to have enough energy to last them through their sleep.

A. pack up               B. build up             C. bring up             D. take up

Answer 1

 B。考查短语动词。 pack up整理；把…打包，bring up提出；教育；养育；呕出；take up拿起；开始从事；占据(时间,地方)，build up逐渐积聚，集结；逐步建立；增进，增强。在本句中build up fat stores表示积累脂肪储存。

【句意】熊在整个夏天到秋天积累脂肪，为了在冬天度过冬眠期。