单选题 Bill is an example of a severely disabled person who has become ______ at many survival skills.

【正确答案】 A
【答案解析】proficient熟练的；persistent坚持不懈的；consistent一贯的；和…；一致的；sufficient足够的。句意：比尔是一个身体严重残废但却熟练地掌握生存技能的典范。