There was a cart at the door, piled with many books, and a cell phone on top.

I turned on the cell phone and played the recording. "Song Yang, looks like you’ve smartened up!” came Deng Chao’s smug voice. “Yes, that test was just a warm-up. This is the real one. As you can see, there is a group of innocent students trapped inside. You have a pile of books in front of you with a question in each book. Once all the questions are answered, you can save everyone. Please send your answers via WeChat. If you get one wrong, then you fail. You must answer all the questions on your own, without help from others. Any request for help or secretly rescuing the hostages will be regarded as cheating. You will be severely punished!"

I handed the phone to one of my classmates and placed...