原因状语从句要译成表示原因的分句。

You jump on the bandwagonwhen you decide to support a candidate because public opinion studies show he is likely to win.

分析：译文中将原句的语序作了前后调整，原因状语前置，而主句被翻译成表示结果的分句。

参考译文：如果民意调查显示某个侯选人很可能会取胜，因此你决定支持他，你就跳上了宣传车。

He says computer manufacturers used to be more worried about electromagnetic interference, so they often put blocks of material inside to absorb stray signals.

参考译文：他说过去的计算机生产商往往更担心电磁干扰，所以他们常常内置一层材料来吸收杂散信号。