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问题 问答题

二十多年前，人患有炎症，一次肌肉注射40万单位的青霉素，抗菌效果很好。现在同样的炎症；一次静脉滴注，青霉素的用量达到320万单位才能达到同样的效果。这是为什么？　　

答案

提示：少数细菌由于变异而具有抵抗青霉素的特性。

单项选择题

TCP/IP （） layer protocols provide services to the application （） running on a computer. The application layer does not define the application itself, but rather it defines （） that applications need—like the ability to transfer a file in the case of HTTP. In short, the application layer provides an （） 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 （） layer consists of two main protocol options—the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

In short, the application layer provides an （） between software running on a computer and the network itself.

A．iteration

B．object

C．interface

D．activity
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填空题

紫外线灯管是人工制成产生（）的低压汞气灯，用于医疗消毒。
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