The typical trenchsystem 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.
This new species of snailfish was discovered 7 kilometres down in the Peru-Chile trench in the south-east Pacific Ocean using a deep-sea baited camera system.
在东南太平洋秘鲁-智利海沟下面的7公里处，使用了深海诱饵式的摄像系统，才发现了这种新品种的狮子鱼。
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The technological process of a practicable hydraulic trenchsystem is discussed, and the layout and the selection of design parameters and the problems in operation are described in this paper.