新概念英语第三册第五课

However ,he had at last been allowed to send a fax in which he infoemed the editor that he had been arrested.
然而,最后他被允许发送一份传真,其间他告知编辑说,他已经被捕.
in which 中的which = fax
这句也可以这么说
However ,he had at last been allowed to send a fax ,in the fax,he infoemed the editor that he had been arrested.
这样,你品品,还不理解,我再来补充解释.