参考答案

正确答案：D
解析：这是一道细节理解题。原文第五段中说到"Paul Anderson，a former British quad racing champion， says the quad's recreational appeal lies in its potential to deliver a safe thrill…The quad bike，in short，provides middle-aged excitement for men who think a Harley might be a bit dangerous．”(前英国四轮摩托大赛冠军选手保罗·安德森说，四轮摩托的娱乐价值在于它既刺激，又安全。……简言之，对于那些觉得哈雷摩托有些危险的中年人而言，四轮摩托车非常刺激。)在这里，appeal＝ attractiveness，即吸引力；而Harley即Harley Davidson motorcycle，又即哈雷摩托，曾连续跻身于美国十大最著名品牌。由此可见，选项D“A quad bike can be exciting without being dangerous．”(四轮摩托令人兴奋却毫无危险。)符合文意，故选D。