used for saying that a change or way of doing sth. is new and very different from the usual way (改变或方式)彻底的，根本的；used for saying that an idea is very new and different, and against what most people think or believe激进的；前卫的A. radicalB. sensibleC. peculiarD. prior

本题考查对单词词义的理解。解题思路是明确题干中给出的英文释义，然后依次分析每个选项单词的含义，找出与题干释义匹配的选项。

• 选项A：“radical”常见释义为“（改变或方式）彻底的，根本的；激进的；前卫的”，与题干中“used for saying that a change or way of doing sth. is new and very different from the usual way (改变或方式)彻底的，根本的；used for saying that an idea is very new and different, and against what most people think or believe激进的；前卫的”释义完全相符。
• 选项B：“sensible”意为“明智的；合理的”，与题干释义不同。
• 选项C：“peculiar”表示“奇怪的；独特的”，和题干所表达的意思不一致。
• 选项D：“prior”意思是“先前的；优先的”，也不符合题干的释义。