英语翻译为什么用have been 不懂

英语翻译为什么用have been 不懂 featival and celebrations of all kinds have been held everywhere since ancient time 这个句子不懂不是应该用 have been holding 为什么用have been held there have been great changes为什么用have been 英语翻译have been 英语翻译have been As long as there have been mice,people have sought a better mousetrap.这句话不懂.As long as there have been mice,people have sought a better mousetrap.这句话为什么用现在完成时? 英语翻译为什么用There have been?我不常见到这样用啊? i have neve been late for work为什么用been I have been sick since yesterday.中have been 是什么是时态为什么要用been. 30分,英语达人进,现在老师讲到过去完成时态,完全不懂~什么have been have gone how long has your room been dirty?为什么不用have?为什么用has?而且我不知道什么时候加been~,还有这些have ever ,for,since,还有什 英语翻译不懂为什么人会变做狗, Nothing could have been more annoying.翻译并解释为什么用could have been 他们结婚十年了 They have been married for ten years 为什么要用have been have been encouragement for me for many years have been encouragement的含义为什么用encouragement you have done me a great service.为什么用have done,为什么不用have been have been doing 为什么还有 have been deadj the room is in the terrible mess ,it can not have been cleaned .为什么用can not have been为什么不用should not have been I have been to Beijing twice 为什么用现在完成时