1. The Roman Empire reached its peak in the 2nd century and began a period of decadence in the 3rd century.
罗马帝国在公元2世纪达到了顶峰，在公元3世纪开始了衰落时期。
2. He indulged in a decadent lifestyle, spending all his money on lavish parties and luxury goods.
他沉溺于颓废的生活方式，把所有的钱花在奢侈的派对和奢侈品上。
3. This chocolate cake is a decadent treat that is sure to satisfy your sweet tooth.
这个巧克力蛋糕是一种颓废的享受，肯定能满足你的甜食爱好。