求解答一个GRE阅读题目。文章来源《花儿阅读配套练习》的练习9的例文3，下面也注明了

jigsaw_beckyUID: 3589627

文章来源《花儿阅读配套练习》的练习9的例文3，下面也注明了原文选自GRE No.6 第三套 section 2。

文章第一段是这个“The use of the pumps has been held back largely by skepticism about advertisers' claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used”.

19题我确实不懂啊，it can be inferred from the passage that, in the course of a heating season, the heating capacity of a heat pump is greatest when?
答案 是A . heating is least essential

我读文章读了几遍都没有找到相关的内容，找到了capacity of a heat pump那段的，就是没有在那一段看见“heating is least essential"  相似的内容

求大神解答！十分感谢！

BarHarborUID: 3594541

下面这句话解释了。你需要推理一下。其实这个很好理解。一般空调的制热功能在零下30度就失效了。

Unfortunately, there is one real problem. The heating capacity of a heat pump decreases as the outdoor temperature falls.

jigsaw_beckyUID: 3589627

BarHarbor 发表于 2015-2-11 22:25
下面这句话解释了。你需要推理一下。其实这个很好理解。一般空调的制热功能在零下30度就失效了。

Unfort ...

谢谢，我懂了！:victory: