In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Q: Article: One day, I was studying at home . Suddenly, there was a loud noise. I went out of my house to see what had happened . What I saw made me scared. A building in my neighborhood was on fire. Some people were using water to put out the fire; others were rushing towards the building to help put out the fire. The building had three floors. The fire started on the first floor. Soon, it spread to the second floor. There were some people on the second floor at that time. Their lives were in danger. A few people jumped out of the window. Luckily, they only got small injuries. Those who were still on the second floor were just crying for help. The people outside didn't know how to help the people inside to get out. Firefighters arrived at last. They fought the fire bravely. Water pipes were used and a ladder was put near the second-floor window. Then the people inside were taken out by the firefighters. They were seriously injured and were taken to the hospital at once. Thanks to the firefighters, the people inside were saved and the fire was put out in the end, but many things, such as desk, pictures and clothes, were damaged.
Answer: Only the second floor of the building
A:
_ was on fire.