Still, advocates of loyalty programs contend that such programs are beneficial because the costs of serving highly loyal customers are lower, and because such loyal customers are less price sensitive than other customers..
a,漏掉了条件，as price sensitivity. 而且不是often，只是may 可能性

为什么不是统计枚举呢？样本是只考虑了经济影响

hey highlight her ongoing efforts to reform sanitary conditions after the war
barrack: 军营

这道题论述的核心在于你有没有为你不需要的功能支付了额外的价钱。A只是一个fact，并没有直接关联这个结论。然后B的话service和你有没有多花钱也没关系。C的话保险钱是必要的，问的是有没有非必要。D的话明显无关。E正好说了Mart不提供基础的，如果你就想买一个基础的，那就不得不买一个功能更好一点的，自然也就多支付了

Krech also contradicts Martin's exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene
M的理论排除了天气作为动物灭绝的原因

争议点：
Conventional theory: the distribution of particles would be increasingly dense toward the center of a meteor stream
computer model: the computer-model meteor stream gradually came to resemble a thick-walled, hollow pipe

既定事实：The researcher found, as expected, that the computer-model stream broadened with time.

A meteor stream is composed of dust particles that have been ejected from a parent comet at a variety of velocities. These particles follow the same orbit as the parent comet

当what在从句中充当主语时，主句谓语动词的单复数由what引导的主语从句中的谓语动词的单复数决定。例如：
(1) What is difficult to understand is A.
(2) What are difficult to understand are A and B.

E选项：adulthood身后少了逗号，插入语必须头尾用两个逗号将其隔开

底层逻辑：保险公司鼓励投保人提早检查+治疗，以防中风需要保险公司赔付。

In reality, however, early trading companies successfully purchased and outfitted ships, built and operated offices and warehouses, manufactured trade goods for use abroad, maintained trading posts and production facilities overseas, procured goods for import, and sold those goods both at home and in other countries.

注意转折

Sixteenth- and seventeenth-century chartered trading companies, despite the international scope of their activities, are usually considered irrelevant to this discussion: the volume of their transactions is assumed to have been too low and the communications and transport of their day too primitive to make comparisons with modern multinationals interesting.

e, important national institution， 没有说

In reality, however, early trading companies successfully purchased and outfitted ships, built and operated offices and warehouses...

d,,并不是management structures的相似性→只是提到起源问题，而不是结构相似性

A 后面两个that是谁引导的宾从？无从得知，反正不是recount，recount that? 说不通
B 错误同A
C 错误同A
D recounted和said没有连词连接，错误

c错在哪里啦？为什么不能like？？？

AC区分：
choice a, 还原 CEO's now earn an average of 419 times more pay than bule-collar workers (do)是可以接受的，但是compared to a ratio of 42 times，比较对象是419 times 和 a ratio
choice b, a ratio作为了419 times的同位语。比较对象依然是a ratio 和42 times。B：ratio不能主动发出compare的动作
choice c, 比较对象是419 times和42 times。correct
choice d,e没有谓语动词

AD区分：首先要理解impose和require是同级的，spend是修饰doctor的
A的逗号在and用法不能用于修饰doctor
只有D的这种根据就近原则才可以

provide the most support和must be true的类型题还是有差别的

本题较难，ron认为BD有idiomatic problem，应该是expect sth没有expect sth to do这一过程好，同时也可以用语感判断，to increase和 become available 这两件事在语义上对应。

when the iron in ilmenite was highly oxidized, its source pipe rarely contained any diamonds.