life cycle

life-cycle的词性：
n.（名词）

1. The course of developmental changes through which an organism passes from its inception as a fertilized zygote to the mature state in which another zygote may be produced.
生活周期：有机物从初期的受精卵到可以产生另一个受精卵的成熟状态所经历的发展变化过程

2. A progression through a series of differing stages of development.
经济周期：经济发展的一系列不同阶段的进展