GRE Text Completion: JiJing 1373-GRE填空机经1373题 - U77R3314Z9AZ4R02A

At one time researchers viewed the placebo effect as (i)____________, a statistical (ii)____________ faced by those attempting an objective evaluation of the efficacy of potentially legitimate therapies. That view has changed: the placebo effect is today seen as an important part of the healing process. A. a boon B. increment C. a touchstone D. annoyance E. an impediment F. deviation