In a computer, which of the following is the longest period？

单项选择题符合IEEE802.3标准的Ethernet网物理地址采用连续编码方法，它使用的地址长度为

单项选择题Which of the following statements describe(s) the properties of a purely segmented memory systemⅠ．It divides memory into units of equal sizeⅡ．It permits implementation of virtual memoryⅢ．It suffers from internal fragmentation