单选题
Research suggests that hypochondriacs A
fell into three categories
; those who have B
a variant of
obsessive-compulsive disorder, those C
whose hypochondria
was triggered by a stressful life event, and those who D
are hypersensitive to
any physical symptoms.
【正确答案】
A
【答案解析】解析：fell into three categories一fall into three categories。句意：研究发现忧郁症患者可分为三类：一类是有强迫性精神障碍变体的患者，一类是由于巨大的生活压力引发了忧郁症的患者，一类是对任何身体病症过于敏感的患者。由主句中的suggests可决定从句中也应使用一般现在时，故fell应改为动词原形fall。