请NN们分析这两道题的比较省略 OG16-90和104

fraqia

OG16-90：Prices at the producer level are only 1.3 percent higher now than those of a year ago and are going down, even though floods in the Midwest and drought in the South are hurting crops and therefore raising corn and soybean prices.
OG16-104:Heating-oil prices are expected to be higher this year than last because refiners are paving about S5 a barrel more for crude oil than they were last year.

为什么一题补足而另外一题可以省略呢？请NN们指教啊～～～

医生吃鱼

1、90题里，正确选项中，比较的是两个主语:"prices now"和 “those of a year ago”

然而，该选项中若是去掉”those of“，比较结构一样成立。比较的对象变成两个时间状语：”now“和”a year ago“

2、104题中，比较的也是两个时间状语：”this year“和”last year“。因为并非比较主语，所以than右面不用补出those等代词。
3、之前有位坛友问过类似的问题，我也回答了，链接如下，供您参考！

关于OG16 #90和#104
http://forum.chasedream.com/forum.php?mod=viewthread&tid=1252036&fromuid=1163152
(出处: http://forum.chasedream.com/)

fraqia

医生吃鱼 发表于 2016-3-25 20:47
1、90题里，正确选项中，比较的是两个主语:"prices now"和 “those of a year ago”

然而，该选项中若是 ...

谢谢您的答复啊～～真有帮助～～

医生吃鱼

fraqia 发表于 2016-3-25 21:46
谢谢您的答复啊～～真有帮助～～

别客气！多多交流！

jeremyniu

赞，思路清晰