140. Since December, when the report came out, the mayor, neighborhood activists (活跃分子) and various parent-teacher associations have engaged in a fierce battle over its validity: over the guilt of the steel-casting factory on the western edge of town, over union jobs versus children's health and over what, if anything, ought to be done.

译文　

自从12月的报告公布以来，市长、社区活跃分子和各种家长教师联合会都参与到一场关于这份报告真实性的激辩中来，内容包括：城镇西边的铸钢厂的罪状、工会工作与儿童健康，以及，如果有什么的话，一些应该做的事。

点睛　

本句的主干是...the mayor, ...activists and...associations have engaged in a...battle...。when引导的时间状语从句对since December进行进一步说明；冒号后over引导三个并列的介词短语对battle over its validity进行详细说明。if anything为插入语，意为“如果有什么的话”。
engage in意为“参加，从事”。如：
I have no time to engage in the shopping. 我没时间购物。
validity意为“真实性，确实性”。如：
The public question the validity of these figures. 公众对这些数据的真实性表示怀疑。
versus意为“对阵；相对”。如：
The final game tomorrow is Brazil versus France. 明天的决赛是巴西队对法国队。