useful adj. 1.有用的,有益的,有效的,有幫助的。 2.〔俚語(yǔ)〕值得稱贊的,精通…的 (at)。 make oneself generally useful 事事有用,事事幫得來(lái)忙 (He must make himself generally useful. 他可事事都干得來(lái))。 a pretty useful performance 相當(dāng)精采的演出。 His wife is very useful at cooking. 他的妻子很會(huì)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 上圖:液晶微滴層層疊加成的三維體可能對(duì)穿透它的光線產(chǎn)生全新而有價(jià)值的影響。 nasa授權(quán)圖片。