Choose the correct completion: If I ______ you, I would accept the challenge. A. am B. was C. were D. have been 答案解析 核心考点：虚拟语气结构 解题思路：虚拟条件句要求用'were'（C）表示与现在事实相反。A、B选项使用真实语气，D选项时态错误。易错点在于混淆虚拟语气和普通条件句的动词形式。 正确答案：C