knapsack

Squatting by one of the walls, I took a little book from my knapsack..我蹲在胡同的墙根，从背包里拿出一本最近出版的小开本的书。

He unstrapped his knapsack, put it, with his stick, on the hedge-bank, and opened the gate..他把背包从身上取下来，连同手中的棍子一起放在树篱坡上，把门打开了。

Fascinated by this magic light-generating globe, he cut it off with his bayonet and put it in his knapsack so he could carry around the light with him wherever he went..他对这个会发光的小球很痴迷，于是用刺刀把它割了下来，放进自己的背包，他觉得这样他就可以把光带到任何他想去的地方了。

knapsack problem,[数]渐缩问题