useful adj. 1.有用的,有益的,有效的,有帮助的。 2.〔俚语〕值得称赞的,精通…的 (at)。 make oneself generally useful 事事有用,事事帮得来忙 (He must make himself generally useful. 他可事事都干得来)。 a pretty useful performance 相当精采的演出。 His wife is very useful at cooking. 他的妻子很会做菜。 adv. -ly ,-ness n.
Above : 3 - dimensional stacked layers of liquid crystal droplets could have some novel and useful effects on light that passes through them . image courtesy nasa 上图:液晶微滴层层叠加成的三维体可能对穿透它的光线产生全新而有价值的影响。 nasa授权图片。