举个例子,trained 和having been trained区别是什么?OJZNo none can walk the wire without a bit of fear unless (trained) very young.为什么不能是having been trained? 什么时候才用having been done?

问题描述:

举个例子,trained 和having been trained区别是什么?OJZ
No none can walk the wire without a bit of fear unless (trained) very young.
为什么不能是having been trained? 什么时候才用having been done?

trained 这里是被动的:they had been trained.
having been trained 是现在完成时的ing形式,但 very young明显是过去,所以不符。

unless 是连词,一般要跟一个从句。这里的trained very young相当一个从句也就是unless he or she was trained very young. 不管是从句还是过去分词词组,都是过去时的被动含义。也就是小的时候被训练过。
having been trained是现在分词的完成被动式,假如放在unless后,还原成从句是完成式,不管是现在完成,还是过去完成,都不合适。
分词的完成式可用于:Having finished his homework, he helped his father work in the garden.先完成作业,后去帮忙。
又:Having been dressed up, he couldn't be recognized at the party.

这个句子属于状语从句的省略,补充完整应该是:
No one can walk the wire without a bit of fear unless he was trained when he was very young.
句子中包含两个状语,一个是条件状语 一个是时间状语,当主从句主语一致 ,并且从句当中含有be 动词的时候,就可以将从句中的主语和be 动词省略掉.
这样就得知 :除非受过训练!
受过训练应该是发生的过去,知道不是“现在”或者“将来”.仅仅是指过去,所以得用 trained
而 having been done是现在完成进行时态,是完成时态的一种,它是指动作从过去某一时间开始一直持续到现在,并且有可能继续进行下去,现在或者当前正在进行着,是与现在有关的.
如:She has been skating for three hours.她已经滑了三个小时.(现在还在滑.)