[originaltext] I had spent my last day in London visiting friends, taking pic

I had spent my last day in London visiting friends, taking pictures, and doing some shopping. I had bought some presents: a shirt for my brother, a book for my sister, (19)and a clock for my father. After travelling in a crowded bus and waiting in the noisy airport building, I was glad to be sitting on the plane at last. In a few minutes, we would be asked to fasten our seat belts and to stop smoking, and then we would soon be up in the sky on our flight to Berlin. But I was mistaken. (20)Ten minutes later, instead of enjoying the beauty of the evening sky from high above the clouds, I was forced to sit in a smoke-filled room with an airline official and a police officer at my side. On the table in front of me was one of my suitcases. The officials were very polite. They asked me to show them my passport, my ticket, and my baggage check. Then I was requested to open the suitcase and to spread out its contents on the table. I did as I was told. The moment I placed the alarm clock on the table, the two officials looked at each other and smiled. (21) Hearing the clock ticking away merrily, I suddenly understood. Someone must have heard the ticking noise coming from my suitcase and thought there was a time bomb hidden in it.
19. What present did the speaker buy for her father?
20. What was the speaker doing ten minutes after she got on the plane?
21. Why did the speaker get off the plane?