比如因果逻辑关系，如果问：为什么要提到原因，我们就找对应的结果，反之亦然，简单来说就是因果互推。我们来看几个例子吧

The author mentions “343 men at one fort engaged on tasks like shoemaking, building a bathhouse, operating kilns, digging clay, and working lead” in order to

A. describe the kinds of tasks soldiers were required to perform as punishment for disloyalty or misdeeds

B. illustrate some of the duties assigned to soldiers to keep them busy and well-behaved when not involved in military campaigns

C. provide evidence that Roman soldiers had a negative effect on the local area by performing jobs that had been performed by native workers

D. argue that the soldiers would have been better employed in the construction of infrastructure such as roads

Paragraph 2: Economic exchange was clearly very important as the Roman army brought with it very substantial spending power. Locally a fort had two kinds of impact. Its large population needed food and other supplies. Some of these were certainly brought from long distances, but demands were inevitably placed on the local area. Although goods could be requisitioned, they were usually paid for, and this probably stimulated changes in the local economy. When not campaigning, soldiers needed to be occupied; otherwise they represented a potentially dangerous source of friction and disloyalty. Hence a writing tablet dated 25 April tells of 343 men at one fort engaged on tasks like shoemaking, building a bathhouse, operating kilns, digging clay, and working lead. Such activities had a major effect on the local area, in particular with the construction of infrastructure such as roads, which improved access to remote areas.

此题提到的句子中有个单词“Hence”说明是结果，那我们要找的是它的原因，大多数的逻辑应该是先原因后结果，所以我们往前推一句，意思是说当士兵不打仗的时候，也得让他们忙着，不然就开始有冲突了，那很明显阴影句子就是一些让士兵忙着而分配给士兵的具体任务，所以此题选择B

Why does the author provide the information about "captive-raised eastern gray squirrels"?

A. To demonstrate the value of experience for successful embryo excision

B. To show the development differences between different species of squirrels

C. To support the conclusion that embryo-excision may be an inborn behavior

D. To suggest that these squirrels learn more quickly than mice, chipmunks, and southern flying squirrels.

Indeed, early germination in white oak acorns appears to have exerted a strong selective pressure on eastern gray squirrels. Several decades ago, John F. Fox demonstrated that when faced with heavy crops of white oak acorns, gray squirrels hide these more perishable food stores, but, when doing so, they carefully cut-off the small embryo at the pointed end of the acorn with a few quick scrapes of their front teeth to prevent the acorn from germinating. Moreover, in experiments with captive-raised eastern gray squirrels having no previous experience with acorns, they also attempt embryo-excision-removal). But they often perform it incorrectly or on the wrong part of an acorn. Thus the behavior may be largely inborn. Although numerous other rodents- such as mice, chipmunks and southern flying squirrels--selectively store red oak acorns, these species do not appear to perform embryo removal. Hence this excision behavior may be unique to a few lineages of squirrels that regularly scatter-hoard acorns. 

提到的这句话的意思是说被圈养的东部的灰松鼠没有之前处理橡子的经验，但是也会尝试把橡子移除，下句话说但是移除的位置不太对，再往下一句有个“Thus”，这种行为是天生的。我们就可以判断阴影句子是原因，那我们要找的就是结果了，所以此题很明显选C