我在做toefl tpo 阅读,是 tpo17 的第一篇,有问题不是很懂,第一个 我不懂得是This development,coming as it did when the bottom had fallen out of the European economy,provided an impetus to a long-held desire to secure direct relati

我在做toefl tpo 阅读,是 tpo17 的第一篇,有问题不是很懂,第一个 我不懂得是This development,coming as it did when the bottom had fallen out of the European economy,provided an impetus to a long-held desire to secure direct relati
我在做toefl tpo 阅读,是 tpo17 的第一篇,有问题不是很懂,
第一个 我不懂得是
This development,coming as it did when the bottom had fallen out of the European economy,provided an impetus to a long-held desire to secure direct relations with the East by establishing a sea trade.
请问 coming as it did when the bottom had fallen out of the European economy,尤其是 had fallen out of the European economy 我完全看不懂
指教,尤其是结构,请帮忙分析下
该句子出自段落
In the fourteenth century,a number of political developments cut Europe's overland trade routes to southern and eastern Asia,with which Europe had had important and highly profitable commercial ties since the twelfth century.This development,coming as it did when the bottom had fallen out of the European economy,provided an impetus to a long-held desire to secure direct relations with the East by establishing a sea trade.Widely reported,if somewhat distrusted,accounts by figures like the famous traveler from Venice.Marco Polo,of the willingness of people in China to trade with Europeans and of the immensity of the wealth to be gained by such contact made the idea irresistible Possibilities for trade seemed promising,but no hope existed for maintaining the traditional routes over land A new way had to be found.

我在做toefl tpo 阅读,是 tpo17 的第一篇,有问题不是很懂,第一个 我不懂得是This development,coming as it did when the bottom had fallen out of the European economy,provided an impetus to a long-held desire to secure direct relati
fall out of 放弃；停止 as it did 其实是
coming as it did when the bottom had fallen out of the European economy 是做前面the development 的状语,理解为 “其实是开始于欧洲经济走出低谷的时候”
翻译：这次发展其实是开始于欧洲经济走出低谷的时候,它对通过建立海上贸易来保护与东方国家的直接联系这一长期存在的愿望产生了推动力.