单选题 Almost everyone has experienced the joy of sports. Nevertheless, thoughtful observers will continue to reflect on the pros and cons of the modern drive to rationalize sports in a quest for the ultimate possible athletic performance.

【正确答案】 D
【答案解析】[解析] 在给出的选项中，debate：辩论，争论；stipulate：规定，保证；signify：象征，预示；porlder：沉思，考虑。只有D选项符合题意，本题答案为D。