在欧洲人接触美洲人之前，他们主要以谷物为生，这些谷物经常遭受歉收。

Before the Europeans made contact with the Americas, they subsisted mainly on grains, grains that often suffered from crop failures.

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国际贸易的迅速扩张也得益于资本的注入，主要起源于西班牙船只从美洲带来的金银。

The rapid expansion in international trade also benefitted from an infusion of capital, stemming largely from gold and silver brought by Spanish vessels from the Americas.

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然而，糙皮病在当时的美洲几乎还不为人所知，甚至在主要以玉米为生的人之间也是如此。

Pellagra was virtually unknown at that time in the Americas, however, even among people who subsisted primarily on maize.

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spent a lot of time going to Latin America to work on poverty alleviation projects,

他在拉丁美洲待了很久，主要处理扶贫项目，

换专业的理由 - SpeakingMax英语口语达人