Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.(氦是钍和铀元素数千年放射性衰变的副产品。)
If left untreated, decay goes deeper and deeper into the tooth.(如果不及时治疗，蛀牙会越来越深。)
The essential condition for the decay of the vacuum is the presence of an intense electric field.(真空衰变的基本条件是存在强电场。)
He pointed out that sugar is a major agent in dental decay.(他指出糖是蛀牙的主要原因。)
The place smelled of decay and neglect.(这地方有一股污浊腐朽的气味。)
There are problems of urban decay and gang violence.(存在都市衰败和黑帮暴力问题。)
The result is tooth decay and gum disease.(结果就是蛀牙和牙龈疾病。)
Both it and its companions would then decay almost instantly into a plethora of less fleeting bits, some of which could be detected.(然后，它与它的伙伴们将会几乎在瞬间衰变为大批寿命更短的微粒子，其中有一些能被检测出来。)
Faustick conducted a two-year survey to find out how to prevent or reduce dental decay.(福斯蒂克进行了一项为期两年的调查，以了解如何预防或减少蛀牙。)
The smell of death and decay hung over the town.(城市上空弥漫着死亡和腐烂的气息。)
