我要在北京工作,在北京我要工作,我在北京要工作. three sentence are correct ,but they stands for different meaning. i mean, you emphasize different aspect. "在北京我要工作"mean: your station is that you are in beijing now,and then you want to work."我要在北京工作" mean:you want to work in beijing ,but maybe you are not in benjing now,and you do not work in beijing now. can you understand? if you have more question ,you can contact me.