下面小编跟大家一起了解考研英语长难句名词性从句，希望对大家的学习有所帮助。
　　长难句
　　But now it is realized that supplies of some of the minerals are limited, and it is even possible to give a reasonable estimate of their "expectation of life", the time it will take to exhaust all known sources and reserves of these materials.
　　难句分析
　　词汇点睛
　　 mineral:矿物质；estimate:估计
　　难点突破
　　 主语从句,同位语
　　结构图示
　　句子分解
　　本句有四个谓语动词: is realized, are limited, is和 will take,并且还有一个并列 连词and 句子,可划分为: A.But now it is realized 主句中,it 为形式主语。 B.that supplies of some of the minerals are limited that引导主语从句。 C.and it is even possible to give a reasonable estimate of their"expectation of life", 并列的 it is even possible to...结构中,不定式to give reasonable...作真正的主语.句子到逗 号之前已经完整。 D.the time it will take to exhaust all known sourees and reserves of these materials the time是"expectation of life"的同位语,进一步解释其含义,面time后面的句子是它的定 语从句.参考译文