答案：C

题目分析：句意:布朗先生是一位有经验的医生，当面对紧急情况时他总是镇定自若。as poor as a church mouse家贫如洗；as busy as a bee忙碌；as cool as a cucumber镇定自若；as strong as a horse非常健康。根据句意故选C。

点评：本题难度适中。固定短语的考查是近几年高考的热点，不仅在单选里，还出现在完形短文改错中。需要考生平时牢记它们的用法及意义。

即学即练：I'm sure he can lift the box. He's      .

A. as poor as a church mouse            B. as busy as a bee

C. as cool as a cucumber                D. as strong as a horse

解析：D。句意：我相信他适合于这个工作,他力大如牛呢!