单选题 Researchers found that teens who slept less than 6.5 hours a night were 2.5 times more likely than those who slept longer to have ______ blood pressure.
A. alternated B. accelerated C. elevated D. startled

【正确答案】 C

【答案解析】[解析] 句子的大意为：研究人员发现，每晚睡眠时间不足6.5小时的青少年患高血压的可能性是睡眠超过6.5小时的青少年的2.5倍。A项alternated“交替”；B项accelerated“加强，加速”；C项elevated“提高，举起”；D项startled“震惊，吃惊”。所以C项符合题意。