Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22.

Galileo Galilei, one of the first modem scientists, (18) _. About twenty years later, he attended the University of Pisa. At first, he studied philosophy, but later he studied mathematics and astronomy. He was interested in the way the earth and other planets move around the sun. He made the telescope (19) _. He also started a 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. (20) _.

Galileo was famous for his study of how things fall. He was the first person to do experiments about this problem. Before that, people thought that heavy things always fell faster than light things. 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 failing bodies. (21) _. The life of the scientist was not always easy in the 1500 s. For example, having incredible scientific ideas, (22) _. 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.

Question 18:  A. being born in Pisa, Italy, in 1564              B. was born in Pisa, Italy, in 1564
C. gave birth in Pisa, Italy, in 1564                D. who was born in Pisa, Italy, in 1564

Question 19:  A. made the examination of far -away things larger and easier
B. tried to examine far-away things which look larger and easier
C. which made far-away things look larger and easier to examine
D. of which far-away things look larger and easier to examine

Question 20:  A. Other scientists helped him do experiments and watched to see what happened
B. Having watched to see what happened, he did experiments
C. He did experiments and watched to see what happened
D. Experiments he did contributed to what happened

Question 21:  A. We can understand our world without this important law
B. It is an important law for understanding our world
C. It is important to understand our world with an important law
D. To understand our world, it is an important law