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的;
;The Canadian researchers randomly assigned about half of the addicts to receive methadone and the other half to receive daily injections of diacetylmorphine, the active ingredient in heroin.
加拿大的研究者对【将】受验者随机分组，一半接受美沙酮的治疗，另一半每天接受注射二乙酰吗啡，主要成分是海洛因【为海洛因的主要成分】。
