Rachel Carson (1907-1964) was a pioneer of the world’s environmental movement through her writing about the protection of the natural world. Her 1962 book Silent Spring made her well known by many people. It describes the harmful changes in the environment of using toxic（有害的）chemicals on farmland.
Carson's career started as a biologist in the US Bureau of Fisheries. In 1951 she published her first book. The Sea Around Us, which became a bestseller. It made her rich enough to leave her job and devote her life to writing. She was s gifted writer. Her next two books were also about the oceans and both topped the book sales lists.
Carson's book Silent Spring completely changed the way America thought about nature. It painted a bleak（荒凉的） future for the whole natural world. It led to a nationwide ban（禁止）on the use of a deadly chemical called DDT, and other toxic pesticides （农药）that farmers used for their crops. Many people say the book led to the creation of America's Environmental Protection Agency.
Since her death. Carson's name has continued to be connected with protecting the environment. There is now a yearly Rachel Carson Book Prize. Norway awards the Rachel Carson Prize to women who have made great contributions to the field of environmental protection. In1980, 16 years after her death, she was awarded the Presidential Medal of Freedom, the highest civilian honour in America.
32. What most probably made Rachel Carson leave her job?
A. She got an award
B. She published Silent Spring
C. The Sea Around Us brought her enough money
D. The US government took notice of her researches
33. Why is the book Silent Spring important to America's environmental protection?
A. It describes a silent spring
B. It topped the book sales lists
C. It changed how America thought about nature
D. It includes all Carson's research achievements
34. What does the underline word "It" in Paragraph 3 mean?
A. The book Silent Spring
B. The way America thought
C. The US Bureau of Fisheries
D. America's Environmental Protection Agency
35. Why was Rachel Carson awarded the Presidential Medal of Freedom?
A. She published the book Silent Spring
B. She did a lot of researches for the US Bureau of Fisheries
C. She donated much money to the Rachel Carson Book Prize
D. She made great contributions to the environmental protection．