无形资产
参考答案：
无形资产是指由特定主体控制的不具有独立实体，而对生产经营长期发挥作用并能带来经济收益的经济资源。
-We all had a lot of fun at the barbecue yesterday. Pity you weren't there.
-I really should have gone with you but I ________ on some important problems.[ ]
A．worked
B．was working
C．would work
D．would have worked
连结脊柱短的韧带有______，_______，_______。
