【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
在线课程【答案】B
【解析】A. pack up打包； B. build up积累； C. bring up养育； D. take up拿起；占据。句意：整个夏天和秋天，熊不断储存脂肪，好使自己有足够的能量冬眠。根据句意选B。