46 A. a philosopher: 1 nhà triết học

47 D. Both A and C: chuyển động của cả trái đát và các hành tinh khác

48 A. Heavy things fell more quickly than light things: vật nặng luôn rơi hơn vật nhẹ 

49C. people who have different scientific ideas D. people who have the belief in science : những người có ý tưởng khoa học khác nhau

50 B. Galileo and his great discovery of falling things : galileo và các khám phá tuyệt vời của ông

galileo was one of the first modern scientists . He was born in Pisa, Italy in 1564. At first he studies philosophy, but later he studies mathematics and astronomy. He was interested in the way the earth and other planet move around the sun. He found out several important facts about our world. He also started the new way of working in science. Before Galileo; scientists did not do experiments. They just guessed about how something happened. Galileo was different. He did not just make guesses. He did experiments and watched to see what happened.Galileo was famous for his study of how things fall. He was the first person to do experiments about this problem. Before, people thought that heavy this go away , fell faster than light thing. He found out that this was not true. He took a heavy ball and a light ball and he dropped them both from a high place. They fell at the same speed. This meant that weight is not important. This is the law of falling bodies. It is an important law for understanding our world The life of the scientist was not always easy in the 1500s. For example, Galileo got into trouble because of his scientific ideas. His ideas were not the same as the religious ideas at the time. Many religious people did not agree with him. During his whole life he had to worry about this. He even went to prison for a while. But no one could stop him from thinking. He continued to look for scientific answers to his questions about the world