The workflow does not work as my think

[=?gb2312?q?weidong=20chen?=]

Hi all:
 
Maybe i have maken mistake.
 
These days i created a workflow template,in some
task
and sub-workflow ,i have set them as 'No general task'
and
assign only one user to these task and
sub-workflow.
> >
> >But in runtime , i found not only the assigned user
> >,but all other user can get the workflow item.
> >
> >i am a new user in workflow.
> >
> >what is the reason?
> >any reply will be thanks.
> >
> >weidong
> >
> >20010507