Hints: 本期学习的字源：deca-=ten十，或作deci-=tenth十分之一 decimal的例句中有破折号 -- San Francisco 单词不需要大写，单词与例句或不同词条之间换行即可。 注解中详细介绍了单词的拆分与释义，是学习字源分析的重中之重！一定记得听写后来看注解！
decade decibel A single crack of gunfire can hit 130 decibels or more, easily exceeding the danger level of 85 decibels. decimal Seconds, minutes, hours and months -- none of these are based on the decimal system. decimate The earthquake of 1989 decimated large stretches of the San Francisco area. decimeter A decimeter equals ten centimeters.
A single crack of gunfire can hit 130 decibels or more, easily exceeding the danger level of 85 decibels. 一声枪响可以达到130分贝以上，轻易地超过85分贝的危险界限。 Seconds, minutes, hours and months, none of these are based on the decimal system. 秒、分、时、月——没有一项是采用十进位计算的。 The earthquake of 1989 decimated large stretches of the San Francisco area. 1989年的地震摧毁了旧金山大部分地段。 A decimeter equals ten centimeters. 一分米等于10厘米。