natural bow静挠度, 自然挠度naturaladj.自然的；天然的；私生的Natural Environment Research Council NOAA自然环境研究理事会natural ecological landscape architecture自然生态园林Natural gangue in air-inflated concrete自燃煤矸石充气混凝土试验研究natural resource-exploiting enterprises资源开发企业natural Korean pine broad-leaved forest天然红松阔叶混交林natural sodium bentonite waterproof layer天然纳基膨润土防水毯natural meaning and non-natural meaning自然意义与非自然意义Natural focal infectious endemic diseases自然疫源性传染病natural binary-coded hexadecimal system自然二进制编码的十六进制Natural science embraces many subjects.自然科学包括许多学科。

1. The natural frequency of specimen decreases as the crack length increases.
   随着裂纹长度的增加，试样的固有频率逐渐减小。
2. The swing is a pendulum with a single natural frequency depending on its length.
   秋千是只有一个固有频率的摆，此频率决定于它的长度。