Trade was the mainstay of the urban economy in the Middle East, as caravans negotiated the surrounding desert, restricted only by access to water and by mountain ranges.

因为商队只能通过水路和山脉进入沙漠，贸易就成为了中东城市的主要经济支柱。

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That's really eye-opening news, since the Appalachian Mountain Range is, of course, thousands of kilometers to the east of the Grand Canyon.

这真是个让人大开眼界的消息，因为阿巴拉契亚山脉当然在大峡谷以东数千公里处。

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His eighteen sixty-six painting "Yosemite Valley" gave many people on the East Coast their first introduction to California's beautiful mountain area.

VOA: special.2009.05.01

He also said that "no-one had any difficulty" while descending the scree slope of the mountain's east ridge.

BBC: Snowdon

Jean Mountain, chair of the East Midlands Business Crime Forum, added the survey would help police authorities identify which areas needed greater support.

BBC: East Midlands businesses to be quizzed on crime

In the valleys of what is now the Swiss canton of Valais, small groups of farmers left their villages and set off east across the mountain passes in search of new lands.

BBC: Hiking the Alpine Walserweg trail