【正确答案】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。

【答案解析】[精解] 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：
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．
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 odd
2)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。
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；