英语语法分析

When the one chair in the room was at its usual place before the table, the canal was unnavigable.

若是屋里唯一的椅子放在了桌前平常的地点，“运河”航行就会受阻。

By 1700 the Virginia frontier had been pushed as far west as the fall line-the point upstream at which the rivers emptying into the Atlantic became unnavigable.

到了1700年，弗吉尼亚州的边境已经向西远推到了瀑布线——上游河流倾泻于大西洋从而不能通航的点。

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。