A.收取郵件的協(xié)議 B.郵件服務器的一種 C.發(fā)送郵件的協(xié)議 D.郵件隊列
A.umount/dev/hdc B.unmount/dev/hdc C.umount/mnt/cdrom/dev/hdc D.unmount/mnt/cdrom/dev/hdc
A.mount/mnt/cdrom B.mount/mnt/cdrom/dev/hdc C.mount/dev/hdc/mnt/cdrom D.mount/dev/hdc