Scientists also have no idea how long it will be before all wild animals in the cages _____.

A．should be set free

B．will be set free

C．are set free

D．would be set free

使用防暴枪进行守库值班的，守库人员应（）

A.将枪支锁在枪柜中

B.枪弹分离保管

C.枪托为折叠式的必须打开枪托

D.子弹严禁上膛