People who have been to the beach, will see that there is a cyclical fluctuationphenomenon of water, which is called tide.
到过海边的人们，都会看到海水有一种周期性的涨落现象，海水的这种运动就是潮汐。
2
The statistical fluctuationphenomenon will appear when the radiation source is relatively weak or the sensitivity of the detector is low.
当射线源比较弱、探测器探测效率低时，常常显示出统计起伏的现象。
3
The characteristic of fluctuation of domestic retail commercial prosperity is rather complicated. This phenomenon is due to the interaction and common effects of various factors.