A private collector is a man who collects_______--A for his own benefitB in privateC on his own

A private collector is a man who collects_______--A for his own benefitB in privateC on his own A private collector is a man who collects_A for his own benefitB in privateC on his own this one must have been in the possession of a private collector 为什么用have,第三人称不是用has吗this one must have been in the possession of a private collector 为什么用have,第三人称不是用has吗 新概念英语,这里为什么用完成时.this one must have been in the possession of a private collector and somehow managed to escape.为什么不是this one muse be in the possession of a private collector ... this one must have been in the possesion of a private collector请问这个句子成分怎么划分?特别是have been 这块! private a. this one must have been in the possession of a private collector and somehow manaed to escape.这是被动语态吗?为甚不同的 看不懂..managed.拼错了 关于主谓一致的单复数问题this one must have been in the possession of a private collector and somehow managed to escape.为什么用Have been 不用 Has been 不是单数么 老版新概念三第一课[A Puma at Large]课后练习题求解212 A private collector is a man who collects .(lines 15-16)a. for his own benefit b. on his own c. in private d. unknown to the public我的选择是（c）,正确答 private=for one's own benefit(最好能给出例句)(NCE3 P17)A private collector is a man who collects ______.a.for his own benefitb.on his own c.in privated.unknown to the public这道题可以用排除法做出,但不知如何正面认定.一个 (新概念英语）A private collector is a man who collects ( ).A:for his own benefit B:on his own C:in private D:unknown to the public 这道题是要根据原文的意思来选择跟原文符合的答案,原文是：this one must have been in the 新概念3中第一课 A puma at large中,HAVE的用法疑惑新概念3中第一课 A puma at large中,有一句话：As no pumas had been reported missing from any zoo in the contry,this one must have been in the possession of a private collector an 关于新概念第三册第一课的问题?有一句是 As no pumas had been reported missing from any zoo in the country,this one must have been in the possession of a private collector.对于肯定推测 have been 是死也不能改的吗? has 可 collector是什么意思 COLLECTOR怎么样 private Private 翻译bire a private tutor