外刊中值得背诵的句子

在本专栏中，我会从英文外刊中选取一些适合参考和背诵的句子或段落，讲解其中的结构和用法。这一篇讲几个特殊的定语从句结构。1 Through agro-biodiversity, we have obtained the immense variety of crops and livestock on which people depend.通过农业生物多样性，我们获得了人们赖以生存的各种作物和牲畜。on which people depend的原形是which people depend on。当定语从句的谓语动词是“动词+介词"时，往往可以把介词提前到which/whom前面。（注意，介词提前时，关系词不能是that：on that people depend）在表示某人所依赖的某事时，就可以用到这个结构：n on which sb depend/rely。还可以在depend/rely后面加上for sth，表示目的，来源于短语depend/rely on sth for sth依靠某事来获得/实现某事。以全球变暖的危害造个句：By altering the environment on land and at sea, global warming undermines the ecosystems on which wildlife ………………………………