16. this is a graph which illustrates...

这个图表向我们展示了......

17. this table shows the changing proportion of a & b from...to...

该表格描述了......年到......年间a与b的比例关系。

18. the graph,presented in a pie chart, shows the general trend in...

该图以圆形图形式描述了......总的趋势。

19. this is a column chart showing...

这是个柱型图，描述了......

20. as can be seen from the graph,the two curves show the flutuation of...

如图所示，两条曲线描述了......的波动情况。