如何在 ubuntu 中挂载“.img”文件（提取的 cubian 文件）

Question

我用了这个命令

sudo mount -t ext2 -o loop Cubian-desktop-r1-a20.img mountpoint

该命令的输出是

mount: wrong fs type, bad option, bad superblock on /dev/loop0,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so