Schools       allow students to do at least one hour's sports every day after school. [ ]

A. would

B. might        

C. should    

D. could

对戒毒人员因毒瘾发作可能自伤、自残或者实施其他危害行为，应当采取必要的自我保护措施，防止发生伤亡事故。 ( )