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 him in charge of typing and sending the messages, while another classmate would keep track of the time.

Then, I quickly picked up the first book and flipped through the contents, finding a card within that read, "No. 9: You are resting at home when you receive a call from a stranger who wants to visit next Friday. You don't want to see him, so you tell the stranger: ‘I’m very busy next Friday. I have a meeting in the morning and a student's wedding to attend at 1:00 pm. Then I have to rush to a funeral for my friend's child at four. It also happens to be my grandfather's seventieth birthday so I really don't have time to receive your visit.’ Which of these following excuses won’t hold up under scrutiny?”

I chewed my finger and contemplated for a few seconds before yelling, "Write the answer for question No. 9. The funeral excuse doesn't hold up under scrutiny. No one starts preparing for a funeral two weeks in advance."

I threw the book and card aside, quickly picking up the second one. This time, the question was, "No. 2: You recovered from an operation and were discharged from the hospital. Your family held a grand party to celebrate your recovery. During the party, you noticed the cake tasted a little strange but the others insisted that it was fine. That night, you suddenly died alone in your home. What is the reason for this?"

My first reaction was poisoning but the question wouldn’t be too complicated so I reread it again and quickly gave the answer. "For No. 2, the answer is–the person in question suffered nerve damage during the operation and didn’t notice the gas leak at home."

"Song Yang, you have five minutes and thirty seconds left!” shouted one of the students. “So hurry up!"

"I know!" I nodded.

I picked up the third book, "No. 7: Early in the morning, in the middle of the open space in the park, you find a man on his back with a Japanese sword missing its hilt buried in the man’s chest. There are no footprints or any suspicious traces within a radius of 30 meters from the body. Is it a suicide or a homicide? And if it’s the latter, then how did the murderer commit the crime?"

Without even thinking, I yelled, "The answer to No. 7 is homicide. The murderer shot the Japanese knife into the victim’s chest with a bow."

I threw the book aside and picked up the fourth one. "No. 1: A patient was stabbed to death with a fruit knife in the hospital. The murder weapon was found in the garden. There were no fingerprints on the handle but many ants crawling all over it. After your investigation, the three most suspicious patients were the abdominal tuberculosis patient in Ward 5, the diabetic in Ward 7 and the patient in Ward 9 suffering from nephritis. Who is the murderer?"

Without a moment’s delay, I shouted, "The answer to No. 1 is the diabetic!"

The diabetic had glucose in his sweat, hence the ants.

The fifth question was, "No. 3: when you were interrogating a criminal suspect, you found that he was both deaf and dumb and could only communicate through writing. After the trial, you said something to him, and when he walked out of the room, you suddenly realized that he was the murderer. What were the words you said to him?"

"The answer for No. 3–you can go!" I blurted.

The boy who was typing the answer suddenly cried out loud, assuming I was asking him to leave. "I’m talking about the answer!" I explained.

Another classmate reminded, "Song Yang, you have three minutes. Come on!"

"No. 6: You and Wang Dali visited Officer Huang in her home. When you arrived, Wang Dali jumped over three steps to ring the doorbell but received no reply. Then he looked through the window and shouted that Officer Huang was murdered. You walked up to the door, only to find that the paint on the steps was still wet. You immediately identified Wang Dali as the murderer. Why?"

The question was very simple so I said, "The answer to No. 6 is Wang Dali knew that the paint was wet, which meant he had visited the scene earlier."

"No. 8: You found a dead man’s body in the barren hills. The man died less than half an hour ago. Afterwards, you caught three suspects who were extras filming a martial arts scene nearby. They played a prostitute, a chivalrous hero and a beggar respectively. They all had bruises on their bodies which they claimed were left during filming, and all three changed out of their clothes during the half hour. You’ve identified one of them as the most probable suspect. Who is it and why?"

After contemplating for half a second, I remarked, "The answer to No. 8 is the beggar. He’s the most likely suspect because beggars are supposed to be dirty. He didn’t have to change out of his clothes and had plenty of time to commit the crime."

There was more than a minute left, sparking a burst of anxiety. My hands trembled uncontrollably as beads of cold sweat dripped down my face.

I took a few deep breaths, opened the next book, and read the question. "No. 5: Shortly after a woman gave birth, the nurse visited the nursery that night itself and found the baby cold and without breath. The hospital decided to hide the matter and replace the child with a newly-born orphan. The mother hadn’t seen her own child after giving birth, so in theory the plan was foolproof. But when she saw the replacement, the mother suddenly cried, ‘This isn’t my child.’ Why?"

"Because the mother killed her baby," I said, rubbing my temples.

There were still two books left. Picking up one of them, I read, "No. 0: A corpse was found in an apartment with the computer and lights in the room still on. On the desk, a flashlight was still turned on. The apartment manager said that the power went out for about 30 minutes last night so the victim should have been murdered within that time period. After investigating the scene, you reached the opposite conclusion–the victim was killed after the power came back. The murderer intentionally turned on the flashlight to mislead the police into believing the crime was committed during the power failure. What’s the proof of your conclusion?"

"Song Yang, you have less than a minute. Hurry up!" urged the student next to me.

I nodded and quickly replied, "The answer to No. 0 is the computer cannot start by itself."

"No. 4: At about 10 o’clock one night, a cyclist on a national highway was killed and the perpetrator escaped. A passers-by saw the car but not the license plate and immediately called the police. When the police arrived, they drove for 15 kilometers along the direction the perpetrator escaped and found nothing. There was neither a fork nor a place to hide within the 15-kilometer stretch. Where did the car go?"

"The perpetrator fled in the opposite direction and drove past the police."

After answering the last question, there were only ten seconds left on the countdown. I waited nervously as the seconds passed and nothing happened.

Just as I breathed a sigh of relief, Deng Chao's voice sounded from the speakers outside, "What a pity. You’ve failed the test..."