The nurse is performing wound care. Which of the following practices violates surgical asepsis

A. Holding sterile objects above the waist.
B. Considering a 1" (2.5 cm) edge around the sterile field as being contaminated.
C. Pouring solution onto a sterile field cloth.
D. Opening the outermost flap of a sterile package away from the body.

通过DMA方式传送一个数据块的过程中，会涉及下面几个操作： Ⅰ．DMAC向CPU发申请总线的请求信号HRQ Ⅱ．I/O设备向DMAC发DMA请求信号，要求进行数据传送 Ⅲ．CPU在完成当前总线周期后暂停操作，向DMAC发响应DMA请求的回答信号 HLDA 并交出总线控制权 Ⅳ．DMAC向存储器发存储器地址信号 正确的操作步骤是

A．Ⅰ、Ⅱ、Ⅲ和Ⅳ

B．Ⅱ、Ⅲ、Ⅳ和Ⅰ

C．Ⅲ、Ⅳ、Ⅰ和Ⅱ

D．Ⅱ、Ⅰ、Ⅲ和Ⅳ