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问题 选择题

已知自然界中铱有两种质量数分别为191和193的同位素，而铱的平均相对原子质量为192.22，这两种同位素的原子个数比应为（   ）

A．39：61

B．61：39

C．1：1

D．39：11

答案

答案：A

利用平均相对原子质量定义即可计算：

解法1 设铱的两种同位素、的原子数分别为，

    解得

解法2

单项选择题

There is little point in looking to artists for insights into political issues. Most of them hold political views that are less insightful than those of any reasonably well-educated person who is not an artist. Indeed, when taken as a whole, the statements made by artists, including those considered to be great, indicate that artistic talent and political insight are rarely found together.
Which one of the following can be inferred from the passage

A．There are no artists who have insights into political issues.

B．A thorough education in art makes a person reasonably well educated.

C．Every reasonably well-educated person who is not an artist has more insight into political issues than any artist.

D．Politicians rarely have any artistic talent.

E．(E) Some artists are no less politically insightful than some reasonable well-educated persons who are not artists.
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单项选择题

有的人对物体的知觉倾向于以外部参照作为信息加工的依据，他们容易受到外来因素的影响和干扰，这种认知方式属于( )

A．沉思型

B．场独立型

C．发散型

D．场依存型
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