【题目】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

【答案】B
【解析】句意：熊在夏秋季节存储脂肪，保存足够的能量以度过冬眠。A. pack up”打包“；B.build up”逐步增加，增强“； C.bring up”抚养， 呕吐“； D.take up”占据， 举起 ，开始从事“。根据句意，选B。