求助一个选项的意思。

鑫多多elynUID：3518454

8. The author is primarily concerned with
(A) showing that a certain interpretation is better supported by the evidence than is an alternative explanation

这个句子没有看懂，求翻译。求分析语法
1，特别不明白 than is an alternative explanation
2，certain和alternative，该怎么理解，对应的什么内容？

原文，36套第六套
The historian Frederick J. Turner wrote in the 1890‘s that the agrarian discontent that had been developing steadily in the United States since about 1870 had been
Line precipitated by the closing of the internal frontier--that is,
5 the depletion of available new land needed for further expansion of the American farming system. Actually, however, new lands were taken up for farming in the United States throughout and beyond the nineteenth century. The emphasis of the presumed disappearance of
10 the American frontier obscured the great importance of changes in the conditions and consequences of international trade that occurred during the second half of the nineteenth century. Huge tracts of land were being settled and farmed in Argentina, Australia, Canada, and in
15 the American West, and these areas were joined with one another and with the countries of Europe into an interdependent market system. Consequently, agrarian depressions no longer were local or national in scope, and they struck several nations whose internal frontiers had
20 not vanished or were not about to vanish. Between the early 1870‘s and the 1890‘s, the mounting agrarian discontent in America paralleled the almost uninterrupted decline in the prices of American agricultural products on foreign markets.

无敌浩克OneUID：3605802

showing that a certain interpretation is better supported by the evidence than is an alternative explanation
structure: showing+宾语从句。
clause： A is better than B
懂了咩？
这是正确选项吗？

鑫多多elynUID：3518454

无敌浩克One 发表于 2015-5-25 17:35
showing that a certain interpretation is better supported by the evidence than is an alternative ex ...

A是正确选项，我知道是宾语从句0 0，是看不懂后面的。。

是这样断结构吗？
showing that （a certain interpretation） （is better supported by the evidence） than（ is an alternative explanation）

翻译成：某一解释充分的被证据所支持，而不是作为一个替补解释？

无敌浩克OneUID：3605802

鑫多多elyn 发表于 2015-5-25 18:50
A是正确选项，我知道是宾语从句0 0，是看不懂后面的。。

是这样断结构吗？

完全正确，就是一种解释比另一种替代解释要好

the agrarian discontent that had been developing steadily in the United States since about 1870 had been
Line precipitated by the closing of the internal frontier这些是不好的解释
后面说的都是证据反驳了这种解释
36套喜欢乱截取老G的文章，这篇原文在36套里面截取的段落之后提了好的那种解释

鑫多多elynUID：3518454

无敌浩克One 发表于 2015-5-26 09:16
完全正确，就是一种解释比另一种替代解释要好

the agrarian discontent that had been developing ste ...

原来这样，感觉36套截取的段落没有特别明显地方可以判断哪个是alternative explantion。。。

我就是搞不清楚alternative explantion指的是原来的解释，还是作者提出的新的解释。。