Q8:

A sudden increase in the production of elephant ivory artifacts on the Mediterranean coast of North Africa occurred in the tenth century.  Historians explain this increase as the result of an area opening up as a new source of ivory and argue on this basis that the important medieval trade between North Africa and East Africa began at this period.

Each of following, if true, provides some support for the historians’ account described above EXCEPT:

1. In East Africa gold coins from Mediterranean North Africa have been found at a tenth-century site but at no earlier sites.
2. The many surviving letters of pre-tenth-century North African merchants include no mention of business transactions involving East Africa.
3. Excavations in East Africa reveal a tenth-century change in architectural style to reflect North African patterns.
4. Documents from Mediterranean Europe and North Africa that date back earlier than the tenth century show knowledge of East African animals.
5. East African carvings in a style characteristic of the tenth century depict seagoing vessels very different from those used by local sailors but of a type common in the Mediterranean.

The percentage of households with an annual income of more than $40,000 is higher in Merton county than in any other county.  However, the percentage of households with an annual income of $60,000 or more is highest in Sommer county.

If the statements above are true, which of the following can properly be concluded on the basis of them?

1. No household in Merton county has an annual income of $60,000 or more.
2. Some households in Merton county have an annual income between $40,000 and $60,000.
3. The number of households with an annual income of more than $40,000 is greater in Merton than in Sommer county.
4. Average annual household income is higher in Sommer than in Merton county.
5. The percentage of households with an annual income of $80,000 is higher in Sommer than in Merton county.

个人感觉：

Q8：题目说北美和东非从10开始贸易导致象牙贸易剧增，所以任何支持论据或者推理过程都可以用来support。B说10世纪前的北美信件没有提及与东非的贸易（是论据成立的必要条件），当然可以支持论点。D说欧洲和北美在10世纪前有提及东非的动物，这个和题目无关，如果说有，那只能说是我们强加上去的联想。

Q30：the percentage of households with an annual income of $60,000 or more is highest in Sommer county.这句话不是很明显说明E么？俺也不明白……