In a formal football match,each team can have three players to________their teammates when necessary.
A:cooperate
B:substitute
C:represent
D:exchange
17、18世纪,当欧洲上空的“理性之光”将人们引向光明时,东方的中国人正逐步被禁锢于“思想的牢笼”。“思想的牢笼”指的是( )