I have just invented a time machine. It can take people to the past or the future for five hours. I got into my time machine and keyed  the words, "1964,11 Niven Road, Singapore", then pressed the button . In a moment, I was in front of a house, 11 Niven Road. I thought that it would be fun to see what my father was like when he was 10 years old. I saw four children looking for a lost dog. They were my father, my uncle Kelvin, my aunt Peek and aunt Janet. I introduced myself as an old friend and agreed to help them look for their dog, Blackie. We wanted to climb a hill and looked into the houses below. When we reached the top, we heard a dog barking. "Blackie !" my father shouted. We looked down and saw Blackie in the house. We knocked on the door of the house and asked the man to return Blackie to us. The man asked us to prove  the black dog was Blackie. My father called out Blackie's name and the dog barked. The man had to give Blackie back to us. We went back to 11 Niven Road and I said goodbye to them. My five hours were almost up. I ran to the machine and soon I was back in my time. What an adventure  ! The passage mainly tells us about   _  .
an adventure to the past an adventure to the future a lovely dog named Blackie the childhood of the writer's father