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问题 单项选择题 A1/A2型题

在《中国药典》中检查药物所含的微量砷盐，常采用（）

A.古蔡法

B.硫代乙酰胺法

C.微孔滤膜法

D.酸碱滴定法

E.非水滴定法

答案

参考答案：A

解析：砷盐检查通常采用古蔡法，或者二乙基二硫代氨基甲酸银法。

单项选择题

梅毒性主动脉炎一般可见

A．内膜层变薄
B．内膜深层见较多泡沫细胞
C．弹性纤维和平滑肌多发性灶状破坏和小瘢痕形成
D．中膜平滑肌显著增生变厚
E．外膜滋养血管缺如，其他正常
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单项选择题

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

It is more and more usual that users of Information Retrieval (IR) systems must face up to response of hundreds or thousands of (66) documents. A significant proportion of them are moreover (67) or redundant. This is a straight consequence of two well - known facts: the incessant growing of documental databases and the lack of ability of most users to define (68) information needs. In such a framework, further effective retrieval techniques are only part of the solution. Interfaces with alternative ways for organizing and (69) the results returned by a (70) would be of great utility assisting users to find relevant documents. Document clustering may play a central role as an effective technique for organizing query results.

（68）是（）

A.concrete

B.special

C.specific

D.particular
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