例205　While warnings are often appropriate and necessary—the dangers of drug interactions, for example—and many are required by state or federal regulations, it isn't clear that they actually protect the manufacturers and sellers from liability if a customer is injured.

【结构分析】While warnings are often appropriate and necessary and many are required by state or federal regulations是个很长的状语从句，其中有两个并列句子，the dangers of drug interactions, for example是个插入语，主干是it isn't clear，后面加上真正的主语从句that they actually protect the manufacturers and sellers from liability，后面是状语从句if a customer is injured。

【亮点回放】此句话的亮点在于状语从句加主句，主句是形式主语it，后面又加上状语从句if，状语从句加主句再加状语从句，很精彩。

【核心词汇】

warnings　警告

appropriate and necessary　适当而且必须的

drug interactions　药物相互作用

state or federal regulations　州或联邦政府规定要求

manufacturers and sellers　生产者和销售者

liability　责任

【参考译文】尽管警告常常是适当而且必须的——比如对于药物相互作用的危险提出警告——许多警告还是按州或联邦政府规定要求给出的，然而（我们）并不清楚，如果顾客受到伤害时，这些警告是不是确实可以使得生产者和销售者豁免责任。