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问题 单项选择题 A1/A2型题

用原子荧光法测定血中微量砷时，最好使用（）

A.干灰化法

B.酸消解法

C.固相萃取法

D.微波消解法

E.溶剂萃取法

答案

参考答案：D

解析：微波消解法消解速度快，几分钟能消解完全，易挥发性元素不易损失。

填空题

用______把工件材料分割开或在工件上锯出______的操作叫锯削。
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单项选择题

TCP/IP (1) layer protocols provide services to the application (2)running on a computer. The application layer does not define the application itself, but rather it defines(3)that applications need - like the ability to transfer a file in the case of HTTP. In short, the application layer provides an (4)between software running on a computer and the network itself. The TCP/IP application layer includes a relatively large number of protocols,with HTTP being only one of those. The TCP/IP (5)layer consists of two main protocol options - the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

空白（4）处应选择（）

A.iteration

B.object

C.interface

D.activity
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