患者，男性，18岁。确诊金黄色葡萄球菌引起的急性骨髓炎。

该药的作用机制是（）

A.抑制β-内酰胺酶

B.抑制DNA回旋酶

C.协同干扰叶酸代谢

D.抑制细菌细胞壁的合成

E.增加细菌细胞质膜的通透性

TCP/IP (71) layer protocols provide services to the application (72) running on a computer. The application layer does not define the application itself, but rather it defines (73) that applications need — like the ability to transfer a file in the case of HTTE In short, the application layer provides an (74) 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 (75) layer consists of two main protocol options — the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

A. application B. sessionC. physical D. transport