1918年时，德军已经建造了一些纵深达到14英里(和22公里)的堑壕体系。
By 1918 the Germans had constructed some trench systems that had a depth of 14 miles (22 km).
第一次世界大战时典型的堑壕体系由2至4条以至更多的一系列壕沟组成，壕沟之间彼此平行，而且纵深可以达到1英里（合1.6公里）。
The typical trench system in World War I consisted of a series of two, three, four, or more trench lines running parallel to each other and being at least 1 mile (1.6 km) in depth.
在那场战争的最后几个月里，彼得斯堡-里士满战区的壕沟体系是堑壕战在19世纪得到应用的先例。
The trench lines of the Petersburg–Richmond theatre of operations in the final months of that war were the foremost example of trench warfare in the 19th century.
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