清朝(前期)对外实行“闭关锁国”政策,对“闭关锁国”政策含义理解正确的是( )
A:禁止一切对外交往
B:封锁沿海港口
C:严格限制对外贸易
D:明朝加强君主专制
54÷9=____
The man has friends in this city,so he often stays at home.