Don't You Blame Me?

"The last few questions are super hard." Shi Nian babbled as she wiped Jiang Jinyan's fingers one by one. "In the end, I got five B's in a row. How could it be possible? I must have made a mistake somewhere for sure. By then, only twenty minutes remained. You can't imagine how nervous I was but fortunately, everything went well. I made a miscalculation in the limit theory we have discussed before. It's so difficult, no matter how many problems I did, I would always make the same mistake."