Co-worker passing on work to me - how to handle?

HI All,
I was going through wat charles, Julie,tina, sachin and arvind brought to my notice....I appreciate your suggestions...
every individual is different so are situations and the way of dealing/addressing them...
tit for tat may work in some situations. although it shd not be encouraged...as i m also aware of its adverse effects.....
being diplomatic can also be done in certain situations
saying "no" ofcourse
managing and/or working in a team
thanks all!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hi Sachin,
Thanks for your suggestion/ Eye opener..
i will positively give thought to them...
Few things i would like to add on as below:
{pls note: i m not defending myself, jst trying to put my views across : do correct me where ever i m wrong}
she is my colleague and not senior
i m at learning stage, i hav 1.5 exp,
the behaviour i stated was becoming very difficult to respond to
i hav been supporting her as and wen required and she to hav been
helping me in the need of hour
as its difficult for me to say "no", following "tit for tat" is even more difficult.
saturday incidence -> i would like to highlight that the manner in which she behaved was wat i was expecting as she has been doing it for long.
the number of candidates that were 3 was fixed- do you feel that 3 candidates who are freshers and are required to be hired for training project purpose will tak full day time?
looking forward for your continued support.