过去式和过去完成时的困惑.帮忙看下句子.As no puma had been reported missing from any zoo in the country,this one must have been in the possession of private collector.请问在这里为什么要把“报道”这个次说成过去完成时（had been reported）,而把拥有（possession）说成have been?
问题描述：
过去式和过去完成时的困惑.帮忙看下句子.
As no puma had been reported missing from any zoo in the country,this one must have been in the possession of private collector.请问在这里为什么要把“报道”这个次说成过去完成时（had been reported）,而把拥有（possession）说成have been?
答
"报道"是过去的动作啊.
而must have been是现在的推测,当然用现在完成时
答
是must have been
must have done 是表示对过去发生的事情的推测，
并非过完。
答
在这里要注意have been前面的must,must have been 中have been 并非现在完成时,而是因为前面的must 导致后面的must必须加have 的原型,这里must have been 表示的是对过去情况的推测