The rough rock walls were like the sides of a deep canal.

粗糙的岩壁就像一条很深的运河的两岸。

《柯林斯英汉双解大词典》

On the western side, the challenge was the Niagara Escarpment, a 23-metre (75-foot) rock ridge. Canal engineer Nathan B.

在运河的西段挑战来自于尼亚加拉悬崖，那是一个高达23米的石质山脊，运河工程师Nathan B。

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So extensive were the wet-season mudslides that in some years more mud and rock fell back into the canal than had been taken out in the first place.

ECONOMIST: The Panama Canal

De Lesseps's insistence that the canal be built without locks had led engineers to try to cut directly through the rock to sea level.

ECONOMIST: The Panama Canal