单选题Read the following text. Choose the best word or phrase marked A, B, C or D
for each numbered blank. The idea that some groups
of people may be more intelligent than others is one of those hypotheses that
dare not speak its name. But Gregory Cochran is {{U}} {{U}} 1
{{/U}} {{/U}}to say it anyway. He is that {{U}} {{U}} 2
{{/U}} {{/U}}bird, a scientist who works independently {{U}} {{U}}
3 {{/U}} {{/U}}any institution. He helped popularize the idea that some
diseases not {{U}} {{U}} 4 {{/U}} {{/U}}thought to have a
bacterial cause were actually infections, which aroused much controversy when it
was first suggested. {{U}} {{U}} 5 {{/U}}
{{/U}}he, however, might tremble at the {{U}} {{U}} 6 {{/U}}
{{/U}}of what he is about to do. Together with another two scientists, he is
publishing a paper which not only {{U}} {{U}} 7 {{/U}}
{{/U}}that one group of humanity is more intelligent than the others, but explains
the process that has brought this about. The group in {{U}} {{U}}
8 {{/U}} {{/U}}are a particular people originated from central Europe.
The process is natural selection. This group generally do well
in IQ test, {{U}} {{U}} 9 {{/U}} {{/U}}12—15 points above the
{{U}} {{U}} 10 {{/U}} {{/U}}value of 100, and have contributed
{{U}} {{U}} 11 {{/U}} {{/U}}to the intellectual and cultural
life of the West, as the {{U}} {{U}} 12 {{/U}} {{/U}}of their
elites, including several world-renowned scientists, {{U}} {{U}}
13 {{/U}} {{/U}}They also suffer more often than most people from a
number of nasty genetic diseases, such as breast cancer. These facts, {{U}}
{{U}} 14 {{/U}} {{/U}}, have previously been thought unrelated. The
former has been {{U}} {{U}} 15 {{/U}} {{/U}}to social effects,
such as a strong tradition of {{U}} {{U}} 16 {{/U}}
{{/U}}education. The latter was seen as a (n) {{U}} {{U}} 17
{{/U}} {{/U}}of genetic isolation. Dr. Cochran suggests that the intelligence
and diseases are intimately {{U}} {{U}} 18 {{/U}} {{/U}}His
argument is that the unusual history of these people has {{U}} {{U}}
19 {{/U}} {{/U}}them to unique evolutionary pressures that have resulted
in this {{U}} {{U}} 20 {{/U}} {{/U}}state of affairs.
【答案解析】[解析] normal正常的；common普通的，共同的；mean平均的；total总共的。一般来说，average表示“平均的”较常用，mean表达这个意义时比较正式。This group generally do well in IQ test, scoring 12—15 points above the mean value of 100”意为“整体来说，这一群体在智力测验方面表现良好，比平均智商值100分高出12～15分”。100分是人们的平均智商数值，故选C。