It is customary for adults to forget how hard and dull and long school is. The learning by 【C1】______ of all the basic things must know is a most 【C2】______ and unending effort. Learning to read is 【C3】______ the most difficult and revolutionary thing that happens to the human 【C4】______ and if you don't believe that, watch an 【C5】______ adult try to do it. School is not 【C6】______ and it is not for the most part very much fun, but then, 【C7】______ you are very lucky, you may find a real teacher. Three real teachers in a 【C8】______ is the best of my 【C9】______ My first was a science and math teacher in high school, my second, a professor of creative writing at Stanford, 【C10】______ my third was my friend and partner, Ed Ricketts. I have 【C11】______ to believe that a great teacher is a great 【C12】______ and that there are as few as there are any other great artists. It might even be the greatest of the arts since the 【C13】______ is the human mind and spirit. My three had these things in 【C14】______ : They all loved 【C15】______ they were doing. They did not tell, they catalyzed a burning 【C16】______ to know. 【C17】______ their influence, the horizons sprung wide and fear we had went 【C18】______ and the unknown became knowable. But most 【C19】______ of all, the truth, that dangerous stuff, became 【C20】______ and very precious. 【C1】