新概念第三册第6课的一个问题，求老师讲解

Question

Two of his assistants had been working busily since eight o'clock and had only just finished.
这句话不太懂，had been working不是过去完成进行是吗，表示还正在work呢.
为什么后面又说had only just finished，已经做完了

Answer 1

Two of his assistants had been working busily since eight o'clock and had only just finished.
他的那两位助手从8点就开始忙活，刚刚完成。
had been working since eight o'clock 是过去完成进行时, 从8点就开始就一直忙活
表示在完成之前，一直在忙活。

had only just finished 是过去完成时,刚刚完成。

因为句子中的动作是说话前某一天内的持续动作，所以前半句用过去完成进行时。后
半句指在那天某个时间点忙活的东西刚刚忙完。

如果仍不好理解，看看是否可以理解下面的句子?

Two of his assistants have been working busily since eight o'clock and have only just finished.
他的那两位助手从8点就开始忙活，现在(在说话时)刚刚完成。
have been working since eight o'clock 是现在完成进行时, 从8点就开始就一直忙活
表示在完成之前，一直在忙活。

Answer 2

后面是不是少抄了几个词啊？had only just finished a little.
如果确认没抄错 追问追问

没抄错，新概念第三册6课原文