—Because she hasn't finished her homework.

    Gina has three brothers. The three boys have different .

    James, Gina's first brother, likes collecting things such as coins and notes(纸币).

    George, Gina's second brother, is a(n)boy. At school, he is good at all his subjects. Of all his subjects he's best at history. His hobby is collecting ancient things. His dream is to be a . He says, "One day I'll solve the of Stonehenge. I'll find out who built Stonehenge and the of building it."

    Ben is Gina's third brother. He has the same hobby as me. He and I like traveling. Because of this, I included him in my of friends. Last weekend Ben and I went camping. On Saturday night we camped by a small lake. During the night, we heard a loud . It woke us up. We thought somebody was moving about. But when we went out of our tent, we didn't see . That made us . That night we didn't sleep well.

    When I was about six years old, I was sure that space aliens had entered my bedroom. One peaceful night, I was in bed, trying to sleep. Suddenly, I heard strange voices whispering(低语) near my bed. I shouted for my parents right away. We looked everywhere but couldn't find anything. I tried to go back to sleep, but the whispering began again. I don't know how many times my parents came to my bedroom that night. I only remembered that none of us could sleep well because of the voices. As a result, I was late for school the next morning.

    "There must be someone hiding in my bedroom, perhaps an alien!" I thought to myself.

    The next night, the same whispering sound came again. Although I was scared, I decided to find the "alien". I searched every corner of my bedroom carefully. Finally, I found it. However, it wasn't the alien that I expected, but an old broken radio in my bookcase. The radio suddenly began to work and the voices came from it.

    Even so, that experience helped me to create a lifelong interest in UFOs and aliens.

    When I was in Grade 5, astronauts were being sent into space for the first time. I would look out of my bedroom's window and search the sky for UFOs. I never saw one, but I did see lots of stars. They were really beautiful and amazing, and maybe the aliens would agree with me.

    We are all interested in mysteries. That is to say that we love some strange and ageless(永恒的)things happening before us. Now here are four amazing unsolved mysteries.