You can find the differences between atime, ctime and mtime by executing command stat FILENAME. As this example,
# stat arabapak.txt File: `arabapak.txt' Size: 42905 Blocks: 96 IO Block: 32768 regular file Device: 23h/35d Inode: 11653804 Links: 1 Access: (0777/-rwxrwxrwx) Uid: ( 3108/ oraara) Gid: ( 201/ dba) Access: 2013-02-18 08:28:38.428104000 +0100 Modify: 2013-02-01 23:43:43.558894000 +0100 Change: 2013-02-04 03:42:37.226786000 +0100
• the last time the file was read, view or displayed. Probably by executing command more, cat, less.
• the last time the file content was modified. Probably by executing command vi
• the last time the file meta data was changed. Probably by executing command chmod, chown.