Bears fat stores throughout the summer and fall to have energy enough to last them through their winter sleep.
A. pack up
B. build up
C. bring up
D. take up
网友回答
A. pack up
(答案→)B. build up
C. bring up
D. take up
解析：考查动词短语的词义区分。句义：熊在整个夏天和秋天加强脂肪的储存为的是有足够的能量来维持他们的冬眠。A pack up 打包 B. build up加强，增多build up =make sth gradually bee bigger C. bring up 提出，抚养长大 D. take up
占时间或者空间，所以B正确。