Yes, I think that's the problem. Same tense is used in different places so when I made the worksheet, the one a assigned in each place is the only one accepted by the program. Thanks for your observation.
Thank you for sharing this worksheet.
A student of mine has tried it (three times, of her own free will!) and some of the answers are not accepted as correct. I can't see the "how it was done" link, but I think maybe you assigned different numbers to each box, so that tenses like the past perfect, which can go in several gaps, have two different numbers associated to it, and she is trying to fit them in the "wrong" gaps. If your students have the same problem, you could try assigning the same number to the gaps that must be filled with the same tense, apparently that makes it work for ANY word that has the same number as the box where it should go, and it doesn't matter that some numbers are repeated.
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