straight up in the teachers face: i am sorry, but i forgot to do it.
we had a teacher who occassionally spent half of the classes to find out if someones homework excuse was wrong. once a guy said that he "forgot" his booklet at home and the teacher went to get his jackets and keys like "no problem, we drive to your place so we can pick it up"...
the other guy just started to cry (it was like 6-7 grade or so), "this isnt necessary, i really forgot it,blablabla"... and the teacher was just standing there and said "is there something you want to tell me??" and everything was over... like 5 minutes later the class was over.
long story short, some teachers just like if someone stands up and says that he didnt do it and awaits/accepts the consequences. because a broken printer/laptop or something like that is bullshit in 98% of the cases.