11. To those who are unaware that animal research was needed to produce these treatments, as well as new treatments and vaccines, animal research seems wasteful at best and cruel at worst.

【分析】多重复合句。句子主干是animal research seems wasteful at best and cruel at worst。介词短语 to those…and vaccines充当句子状语，其中who are…vaccines是一个定语从句，修饰those，而在这个定语从句中，that引导的从句作unaware的宾语。
【译文】对于那些不清楚获得这些治疗方法以及新疗法和新疫苗都需要进行动物实验的人来说，动物实验似乎说得好听点是浪费，说得不好听是残忍。
【点拨】l)vaccine含义为“疫苗”。2)at best…at worst …意为“往最好处想…从最坏处想…”。

12. They should be quick to respond to letters to the editor, lest animal rights misinformation go unchallenged and acquire a deceptive appearance of truth.

【分析】复合句。 They should be quick to respond to letters是句子主干。lest引导条件状语从句，从句的两个谓语结构由and连接。
【译文】他们应尽快答复致编辑的信件，以免动物权利的错误信息没能引起任何质疑，同时获取了带伪装性的真理外表。
【点拨】1)respond to a letter/letters 意为“回信”。2) misinformation 意为“错误信息”。3) unchallenged 意思是“未受到挑战的，未引起争论的，未受质疑的”。