How deep is your deceipt

I am a teacher. Since January 2013, I have been teaching the “Operating Systems” course at the Engineering Faculty of UNAM . And yes, that means May and November are highly stressful months, where I have to review the work done by my students and… sigh … come to the difficult decisions leading to a numerical score that will, in very very short, represent the 64 hours they spent listening to me…