回复看译文及句子结构分析^_^

Only after studies provided evidence of the harmful effects of such programs has it been possible to modify TV programming policies.

游客，如果您要查看本帖隐藏内容请回复

只有在大量的证据指出这样的节目会产生不良的影响，电视节目的审查政策才会有所改变。

Totally agree with upstairs

Only after studies provided evidence of the harmful effects of such programs has it been possible to modify TV programming policies.

只在对这些节目所产生的负面影响研究取证之后才有可能对播放电视节目的基本政策进行修改

MS没差多少