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解析：Franz Boas and Edward Sapir were forerunners of American structuralism.Boas studied the American Indians’languages and found that the traditional grammatical model could not be used to analyze the structure of those languages.He had to describe those languages as they were used. This started American structuralism.
Leonard Bloomfield accepted the theories and principles of Franz Boas.He argued that linguists should describe instead of prescribing what people say and should take an inductive approach in analyzing data. In 1933, he published the book Language. It soon became the bible of American structuralism.