以下哪项是最容易产生生理依赖、耐药物性与戒断反应的精神活性物质()
A.抗抑郁剂
B.兴奋剂
C.吗啡制剂
D.致幻剂
E.镇静剂
参考答案:C
Mr. Black is working ______ his project at home. [ ]
A. to
B. on
C. in
D. at
位错