Which of the following sentences BEST exemplifies the "conciseness" feature of specialized English (本题2分)A. The material should be pre-treated before it is processed.B. We must do various experiments before a new composite material is designed.C. The material should be pre-treated before being processed.D. If it is possible, the purification of raw material should be done.

本题考查专业英语“简洁性（conciseness）”这一特征的理解与运用。解题思路是分析每个选项的句子结构和用词，判断哪个选项在表达相同意思的情况下最为简洁明了。

• 选项A：“The material should be pre - treated before it is processed.” 此句中 “it is processed” 表述较为完整，但 “it” 指代 “the material” 有一定的冗余，因为前文已经明确提到了 “the material”。
• 选项B：“We must do various experiments before a new composite material is designed.” 该句重点在于描述在设计新材料之前要进行各种实验，与专业英语简洁性强调的去除不必要成分、直接表达核心内容的要求不太契合，句子相对较长且包含了一些非核心的描述 “We must do”。
• 选项C：“The material should be pre - treated before being processed.” 此句使用了 “being processed” 这种分词形式，省略了 “it is”，使句子更加简洁，同时清晰地表达了材料在加工前需要预处理的意思，符合专业英语简洁性的特征。
• 选项D：“If it is possible, the purification of raw material should be done.” 其中 “If it is possible” 是一个比较啰嗦的表达，在专业英语中可以更简洁地表达，而且 “the purification of raw material” 表述也可以更简洁，所以该选项不符合简洁性要求。