129. The trouble is that part of the recent acceleration is due to the usual rebound that occurs at this point in a business cycle, and so is not conclusive evidence of a revival in the underlying trend.

【结构分析】

1、该句的主语是The trouble，谓语是系表结构，第一个表语是that引导的从句：从句中的主语是acceleration，表语是due to...形容词短语，介词to后的名词the usual rebound又由that引导的定语从句（that occurs at this point in a business cycle）修饰。

2、第二个表语由and so连接，与前面表语是并列加因果的关系。due to...意为"由…引起的"。如：The team’s success was largely due to her efforts.

【参考译文】

问题在于，近年发生的生产力快速增长现象部分是由于商业周期到了这时候通常会出现的反弹造成的，因而它不是经济复苏已经是潜在趋势的确凿证据。