这个B的revision咋理解。。。谢谢老师

问题如下：

Which of the following statements is the best description of the characteristics of economic indicators?

选项：

A.Leading indicators are important because they track the entire economy. B.Lagging indicators, in measuring past conditions, do not require revisions. C.A combination of leading and coincident indicators can offer effective forecasts.

解释：

C is correct. While no single indicator is definitive, a mix of them—which can be affected by various economic determinants—can offer the strongest signal of performance.

领先指标是预测经济而非跟踪经济，所以A选项错误。

滞后型指标也需要 revisions，以检验指标的正确性，所以B选项错误。

将领先型与同步型指标结合，并且如果两者能给出相同的结论指向，那么给出的信号就是有说服力的，所以C选项正确。