ac patch is the patch from Alan Cox. he changes some kernel code base on his own design. his main modification is on scsi part. of course full list of his modifications can be found from doc.
snapshot is the latest one, even is not stable as a 2.x.x, but has some new features, of course also some bugs.
Prepatches are the equivalent to alpha releases for Linux; they live in the testing directories in the archives. They should be applied using the patch(1) utility to the source code of the previous full release. The testing/incr directories contain automatically generated patches from one prepatch to another.
Prepatches may be poorly tested, and may in fact not work at all. Use on your own risk; if you use one and run into a problem please see Reporting Linux Kernel Bugs on the front page.
Prepatches with -rc in the name are considered release candidates and may become full versions. It is therefore particularly important that those get tested.
The -dj patches are a set of patches, released by David Jones, against the official beta kernel series. They are frequently more experimental in nature than the official series. These patches are available in David's kernel directory:
hehe, why u need a translated version. i have a friend whose english is very poort, but he can read thses computer document. usually these are plain english very easily to be understanded. so try to read them directly