帮忙用英语写一篇过去发生的事。

Last Sunday,While I was walking down the street,I saw a UFO landed in front of me.An alien got out.I was very surprised.The alien went into a souvenir shop,and I followed it.While it was seeing the souvenirs,the shop assistant called the police. Before the police arrived,the alien left the shop, and went into a Museum of Flght.While the alien was in the museum, I called the TV station. Isn't that amazing?