"We see the foundations wearing away, the stone steps crumbling, the unnavigable canals. 他说：“我们眼看着地基逐渐磨损，石头台阶碎裂，河道也不再通航。”
It is 822 mi (1,323 km) long.It is torrential for most of its course and is unnavigable. 它长约822哩（1,323公里），由于其大部分河段皆湍急汹涌，故难以航行。
Corporate Websites: I recently co-judged a competition of nominated best-of-class business websites, and I was aghast at how unnavigable and useless most of them were. 企业类网站: 近期我参与了一项最佳商业网站的评委工作，却惊奇地发现这些网站中的大多数都是不能正常运行或者毫无价值的。
