填空题

A. 10 percent to 25 percent for the proportion of workers who use drugs occasionally on the job
B. determine exactly when simple drug use becomes abuse
C. the 1920s until the 1960s
D. the 1960s until the 1970s
E. signals passing through the nervous system Treatment of drug abuse in the United States was practically nonexistent from ______.

【参考答案】

C