Hie, so my Ubuntu show`s that i have 100MB of updates to download, but my internet connection is slow And my question : Can I start all updates and later(in new session) continue downloading?

Yes. When you start updating, apt will first download all the files and only then start installing them (and even then it first checks out a few things). So if you cut off the download, the already downloaded files should stay in the cache and you should be able to continue from there. Yet again, if the packages seem to disappear, your settings tell apt not to keep cache on the disk; in that case you'll need to alter your apt configuration. But in a normal situation, yes, you can continue download when you want.

If you issue the apt-get --help command then the following is displayed.

Here is the switch that you are looking to use.

-d Download only - do NOT install or unpack archives


So the command would be:

sudo apt-get update
sudo apt-get upgrade -d

----------------------------------------

apt-get help
apt 0.6.43.3ubuntu2 for linux i386 compiled on Apr 18 2006 19:46:38
Usage: apt-get [options] command
apt-get [options] install|remove pkg1 [pkg2 ...]
apt-get [options] source pkg1 [pkg2 ...]

apt-get is a simple command line interface for downloading and
installing packages. The most frequently used commands are update
and install.

Commands:
update - Retrieve new lists of packages
upgrade - Perform an upgrade
install - Install new packages (pkg is libc6 not libc6.deb)
remove - Remove packages
source - Download source archives
build-dep - Configure build-dependencies for source packages
dist-upgrade - Distribution upgrade, see apt-get(8)
dselect-upgrade - Follow dselect selections
clean - Erase downloaded archive files
autoclean - Erase old downloaded archive files
check - Verify that there are no broken dependencies

Options:
-h This help text.
-q Loggable output - no progress indicator
-qq No output except for errors
-d Download only - do NOT install or unpack archives
-s No-act. Perform ordering simulation
-y Assume Yes to all queries and do not prompt
-f Attempt to continue if the integrity check fails
-m Attempt to continue if archives are unlocatable
-u Show a list of upgraded packages as well
-b Build the source package after fetching it
-V Show verbose version numbers
-c=? Read this configuration file
-o=? Set an arbitrary configuration option, eg -o dir::cache=/tmp
See the apt-get(8), sources.list(5) and apt.conf(5) manual
pages for more information and options.
This APT has Super Cow Powers.