单选题
Clark felt that his ______ in one of the most dramatic medical experiments of all time was worth the suffering he underwent.
【正确答案】
B
【答案解析】(participation参与)。句意为：克拉克觉得他参加了一次有史以来最为激动人心的医学实验，他经历的痛苦是值得的。A．presentation展示，描述；C．apprehension理解，领悟；D．appreciation欣赏。