data在某一个时间段固定不变：fixed in time

　　在一系列的时间段中转变：changes over time

　　持续变化的data在不同情况下:

　　增加：increase / raise / rise / go up ...

　　减少：decrease / grow down / drop / fall ...

　　波动：fluctuate / rebound / undulate / wave ...

　　稳定：remain stable / stabilize / level off ...

　　最常用的两种表达法：

　　动词 副词形式

　　形容词 名词形式

　　1. Verb Adverb form

　　The number of XXX

　　 increase/jump/rise/decrease/drop/fall/fluctuate...

　　 insignificantly/significantly/slightly/suddenly/rapidly/dramatically/sharply/steeply/steadily/gradually/slowly...

　　 from to / between and

　　2. Adjective Noun form

　　There was a sudden/rapid/dramatic/significant/sharp/steep/steady/gradual/slow/slight

　　 increase/jump/rise/decrease/drop/fall/fluctuation

　　 in the number of XXX from to / between and

　　描述稳定的data：

　　The number of XXX remained steady/stable from to / between and

　　The number of XXX stayed the same from to / between and