Miss Kate taught physics in a New York school. Last month she was explaining to one of her classes about sound, and she decided to test them to see how well they had understood her explanation. She said to them, "Now, I have a brother in Los Angeles. If I was calling him on the phone, and at the same time you were 80 meters away, and were listening to me from across the street, which of you would hear what I said earlier, my brother or you and for what reason?"

A boy at once answered, " Your brother, Miss Kate, because electricity travels faster than sound waves(声波).

"That's very good." Miss Kate said, but then Jenny said, "I don't agree. Your brother would hear you earlier because it is 11 o'clock here, it's only eight o'clock in Los Angeles."

                                Where is the true home of hamburger?

     The kind of beef we see in hamburgers , minced(切碎)beef, was possibly invented by Mongolians over 800 years ago. But who first put the beef between pieces of bread and called it a hamburger? Three different cities in the United States all say that they were the first to invent America's favorite food.

     Some people say that Fletcher Davis, from Athens, invented hamburgers. “Old Dave,”as people called him, was selling minced beef sandwiches in his lunch bar as early as the 1880s. Some years later, they say that a group of Germans called①his sandwich a “hamburger” because people from the German city of Hamburger ate this kind of beef.

     Other people believe that the hamburger came from a different American city.②coincidentally, its name was also Hamburg. The Menches brothers were selling pork sandwiches at a fair in 1885, but when there was no more pork, they used minced beef and gave it a new name, the “hamburger”.

     The third possible inventor of the hamburger was Charlie Nagreen, also known as “Hamburger Charlie,”from Seymour. He said that in 1885 he invented the world's first hamburgers. Seymour now celebrates the invention of the hamburger every year. In 1989, it was the home of the world's largest ever burger—over 2,500kg!

    This is a photo of Betty's {#blank#}1{#/blank#} .There is a big new desk {#blank#}2{#/blank#} the blackboard. There are some flowers on the teacher's desk and {#blank#}3{#/blank#} under the teacher's desk. There are some green desks and chairs for {#blank#}4{#/blank#}. There are {#blank#}5{#/blank#} students in Betty's class.

Bex Lindsay's dream was to be a host. From a young age, she was very 1 in radio. In her childhood she often pretended (假装) to host her own shows on Bex Radio while 2 her parents' CDs. At that time Lindsay wanted very much to work at Fun Kids, a radio station 3 young listeners, so she sent them a strange recording, hoping to be accepted.

"In the old host-to-be performance, the final thing you were 4 to do was to jump on a trampoline (蹦床) while interviewing 5, "she told the reporter, "I didn't have a trampoline and I didn't want to do it in front of anyone else, so I interviewed myself while jumping on my bed, having the recording made. "

Lindsay's recording really 6 and she was asked to host the Sunday breakfast show. Now she hosts a popular program and she loves radio more than ever. She says, "My 7 as the host is kind of to be a listener, so I will ask questions that other people would want to ask."

When she is asked how she has been 8, Lindsay says, "First of all, keep the dream in your mind and 9 give up. "She adds, "Hosting isn't about how high up in the world you are; its about having a good 10 and a good idea. Go and do it."

Today there are policemen everywhere, but in 1700 London had no policemen at all. A few old men used to protect the city streets at night and they were not paid much. 

About 300 years ago, London was starting to get bigger. More and more people went to live and work there. However, there were many thieves in the streets, so most people wanted to stay in their homes as much as possible. 

In 1750, Henry Fielding started to pay a group of people to stop thieves. They were like policemen, but they were called "Bow Street Runners" because they worked just near Bow Street. Fifty years later, there were 120 Bow Street Runners, but London became very big and needed more policemen. 

In 1829, the first London Police Force was started with 3, 000 officers. Most of the men worked on foot, but a few rode horses. And until 1920 all the police in London were men. 

Today London Police are quite well paid and for the few police officers who still ride horses, the pay is even better than for the others. 

Leonardo da Vinci is famous as an Italian painter. He showed great {#blank#}1{#/blank#}and {#blank#}2{#/blank#} ability when he was young. Besides, he also had many {#blank#}3{#/blank#} ,for example, his notebooks with interesting drawings of flying machines. 

Dinosaurs lived {#blank#}4{#/blank#}on Earth before human beings and had different shapes. Some were small, {#blank#}5{#/blank#} were big. Today, we can {#blank#}6{#/blank#} about them from their fossils. 

Once upon a time, a king challenged {#blank#}7{#/blank#}old man to a chess game and finally lost. He {#blank#}8{#/blank#} his men to collect a bag of rice to give the wise man. However, there wasn't{#blank#}9{#/blank#} rice to put {#blank#}10{#/blank#}all the squares.