1. 衰减,衰退：decay tube == 衰变管 | decaying == 衰减,衰退 | decaying conduction current == 衰减传导电流
2. 颓坏：decayed /腐烂的/ | decaying /颓坏/ | deccelarate /减低速度/
3. 腐蝕作用：Debris 碎片 | Decaying 腐蝕作用 | Deciduous forest 落葉林
4. 腐朽：eroded rock 被腐蝕的岩石 | decaying 腐朽 | matter 問題