完形填空求助Carl Sagan was a distinguished scientist,author,and ed

完形填空求助
Carl Sagan was a distinguished scientist,author,and educator who wastrained in b_____ astronomy and biology.He s________ as a leading adviser to the National Aeronautics and Space Adminstration from the time American space exploration b________ ,and he received many awards for his contributions to planetary science and environmental preservation.Sagan also captured the imaginations of millions of people with an interesting book c_________ Life in the Universe and other essays.His gift for explaining difficult s______ concepts in ways that people could easily understand helped make h_____ one of the finest science educators in the world,Carl Sagan will always be r_____ as a bright and gifted scientist