emerge -pv gnome

[unix like]

[The Doctor]

The problem is that consolekit requires udev-182, which is not installed. Your current version is udev-171-r5.

First you can try running emerge -avuND world to update everything and see if the message goes away if you are running the unstable branch, ie, ~amd64, ~x86, etc. Be aware that the new udev is not playing nicely with /usr on a separte partition without a initramfs. If you used genkernel or /usr is not a separate partition, you will not have a problem. After you complete the update, the block should go away.

you can try running emerge -pv --backtrack=30 gnome as per the portage output and see if that solves the problem.

If you are running on the stable branch, then you can proceed as follows, again be aware about the new quirk in udev above.
If the problem is not solved by these steps, then I would guess that the problem is that >=udev-182 are unstable and you are not running on the unstable branch. If you are not running on the unstable branch, then you will need to accept the keywords for udev to continue. Here is how to do that:
1) open the keywords file. You will need to create it if you have not already done so: nano -w /etc/portage/package.accept_keywords
2) add the line <=sys-fs/udev-182-r3 if you are running amd64. use r2 if you are on x86. Don't use the 182 version number because that will not install due to a bug.

note the inequality. You will want to only include the version that solves your problem and then return to the stable version as quickly as possible by not updating to newer unstable versions. Don't down grade important packages if you can help it. Some, like glibc and qt, will break your system.

In general, you want to avoid mixing branches like this if you can help it. When you do things tend to break.
_________________
First things first, but not necessarily in that order.

[BillWho]

unix like,

If you haven't done an update yet I would suggest doing so before installing gnome.

[unix like]

when I emerge -avuND world

[BillWho]

unix like

My bad there with the mask This will correct it:

[unix like]

But new problems emerges,now I have to reinstall again.so bad!

[The Doctor]

In general, re installing will NOT solve your problems. It will only give you the chance to make the same mistakes again. If you have not already re-installed, then post your /etc/make.conf and the output of eselect profile list
_________________
First things first, but not necessarily in that order.

[unix like]

[BillWho]

unix like

What profile are you using?

[unix like]

my desktop is gnome,and do I need to type ACCEPE_KEYWORDS="~amd6" into the file make.conf

[The Doctor]

You do not need ACCEPE_KEYWORDS="~amd6" in your make.conf
If you want the newest bleeding edge software and the bugs that come with it, then you can use it.
If you prefer stable packages with only the needed testing packages, add them to /etc/portage/package.accept_keywords (you will need to create this file)
entries look like this:

[unix like]

got it

[The Doctor]

Taking a close look at your make.conf use varable, it looks messy and chaotic. you can look up what flags do at http://www.gentoo.org/dyn/use-index.xml.

hal is dead and removed so your "hal" flag is useless. You set -kde and handbook, but handbook only generates entries for kde4 you also have kdeenablefinal, which is also kde specific. Most everything should be in the gnome profile. make.conf is best used for global fine tuning of your profile. python is listed twice. This is not really an issue, but it is a bit messy. The static and static-libs are not something you generally want to set. Do not set them unless you know what you are doing. For package specific flags, and I believe I see quite a few, you should set them on a per package basis in /etc/portage/package.use as they do different things in different packages.

Using a quick look at it, I think I would do this:

WANT="gtk firefox declarative cups mplayer pdf dvd samba"
DONTWANT="-kde -qt4 -qt3 -java"
USE="${WANT} ${DONTWANT}"

I included -java and samba here as they were set this way, but I would tend to reverse that and say java and -samba because everything uses java but unless you know what samba is, you will not be using it. I believe that the gnome profile would select just about everything else, except some of the media flags would should be controlled through package.use.

You can always go back and change your use settings of course. These are just a few random thoughts on your config.
_________________
First things first, but not necessarily in that order.

[unix like]

yeah,what you said makes sense,penguin!my make.conf file is not a bit messy but very very messy.Because when I install applications,I will add available VARS into USE according to the hints of screen,so it looks very chaotic.Luckily,before this I have finished the installation of gentoo including gnome finally,although my deed looks hurry and chaotic.But I am very happy and have the sense of achievement. It really take me many time just installing gnome!
Until I entered the gnome,did I found that I cann't use keyboard but mouse can,returned back to command line,both keyboadr and mouse are ok .I also did not find the grub.conf in /boot/grub.How do I solve the problems,please?

[The Doctor]

Ok, mouse and keyboard should be controlled by a driver in X11, so you should add this line to your make.conf:

[unix like]

Thank you for your advice.It's very very useful.I do as you said,it is totally right!

[gorkypl]