71) But even more important, it was the farthest that scientists had been able to looksintosthe past, for what they were seeing were the patterns and structures that existed 15 billion years ago.

句子分析：

第一、句子可以拆分为三段：But even more important, it was the farthest that scientists had been able to looksintosthe past, / for what they were seeing were the patterns and structures / that existed 15 billion years ago.

第二、句子主干结构是：主句+ for +原因状语从句。1)主句是强调句it was... that...被强调部分the farthest是后面句子的状语，可以理解为scientists had been able to look the farthestsintosthe past2) for...引导的原因状语从句是一个系表结构，what they were seeing是从句中的主语，that...是名词表语the patterns and structures的定语从句。

第三、词的处理：even more important (省略)更为重要的是the patterns and structures (宇宙云的)形状和结构15 billion years ago 150亿年前
完整的译文：71)但更为重要的是，这是科学家们所能观测到的最遥远的过去的景象，因为他们看到的是150亿年前宇宙云的形状和结构。

72) The existence of the giant clouds was virtually required for the Big Bang, first put forward in the 1920s, to maintain its reign as the dominant explanation of the cosmos.

句子分析：

第一、句子可以拆分为三段：The existence of the giant clouds was virtually required for the Big Bang, / first put forward in the 1920s, / to maintain its reign as the dominant explanation of the cosmos.

第二、句子的主干结构是一个简单句。1)整体结构是：The existence... was virtually required for..., to maintain...2)first put forward in the 1920s是过去分词短语作插入语，说明前面的名词the Big Bang3)后面的不定式短语是补语。

第三、词的处理：the giant clouds 巨大的(宇宙)云virtually 事实上，实际上，实质上the Big Bang 大爆炸理论first put forward 首创的，开始提出的in the 1920s 二十年代to maintain its reign as 以保持……的地位explanation of the cosmos 对宇宙(起源论)的解释
完整的译文：72)巨大的宇宙云的存在，实际上是使二十年代首创的大爆炸论得以保持其宇宙起源论的主导地位所必不可少的。　

　73) Astrophysicists working with ground-based detectors at the South Pole and balloon-borne instruments are closing in on such structures, and may report their findings soon.

句子分析：

第一、句子可以拆分为三段：Astrophysicists working with ground-based detectors at the South Pole and balloon-borne instruments / are closing in on such structures, / and may report their findings soon.

第二、句子主干结构是：1)主语+并列谓语Astrophysicists...are closing...and may report...2)分词短语working with ground-based detectors at the South Pole and balloon-borne instruments是主语的定语。

第三、词的处理：working with 使用，以……为工作手段ground-based detectors 陆基探测器the South Pole 南极balloon-borne instruments 球载仪器are closing in on 正越来越近structures 云系findings 观测结果
完整的译文：73)天体物理学家使用南极陆基探测器及球载仪器，正越来越近地观测这些云系，也许不久会报告他们的观测结果。

74) If the small hot spots look as expected, that will be a triumph for yet another scientific idea, a refinement of the Big Bang called the inflationary universe theory.

句子分析：

第一、句子可以拆分为三段：If the small hot spots look as expected, / that will be a triumph for yet another scientific idea, / a refinement of the Big Bang called the inflationary universe theory.

第二、句子的结构：1)主干结构是“If引导的条件句，主句”。2)look as expected是look as they are expected的省略，意思是“看上去和预想的一样”。3)another scientific idea和后面的短语a refinement of the Big Bang是同位语关系。4)过去分词短语called the inflationary universe theory作定语，修饰the Big Bang.

第三、词的处理：the small hot spots 小热点refinement 更完美，提炼，改进the inflationary universe theory 宇宙膨胀说(理论)
完整的译文： 74)假如那些小热点看上去同预计的一致，那就意味着又一科学论说的胜利，这种论说即更完美的大爆炸论，亦称宇宙膨胀说。

75) Odd though it sounds, cosmic inflation is a scientifically plausible consequence of some respected ideas in elementary-particle physics, and many astrophysicists have been convinced for the better part of a decade that it is true.

句子分析：

第一、句子可以拆分为三段：Odd though it sounds, / cosmic inflation is a scientifically plausible consequence of some respected ideas in elementary-particle physics, / and many astrophysicists have been convinced for the better part of a decade that it is true.

第二、句子的结构：1)主干结构是倒装的让步状语从句+主句。Odd though it sounds = though it sounds odd2) consequence前后有多重定语。3) and many astrophysicists have been convinced为被动结构。4) that it is true是宾语从句。

第三、词的处理：cosmic inflation 宇宙膨胀说scientifically plausible consequence 科学上可信的推论in elementary-particle physics 基本粒子物理学convinced 被说服，相信for the better part of a decade 七八年来
完整的译文：75)宇宙膨胀说虽然听似奇特，但它是基本粒子物理学中一些公认的理论在科学上看来可信的推论。许多天体物理学家七八年来一直认为这一论说是正确的。