【正确答案】正确答案：Saussure occupies such an important place in the history of linguistics that he is often described as "father of modern linguistics": (1) The book Course in General Linguistics (1916), which is the most important source of Saussure's ideas, marked the beginning of modern linguistics. (2) Saussure was the first to notice the complexities of language. He believed that language is a system of signs, called conventions. He held that the sign is the union of the signifier and the signified. (3) By providing answers to questions concerning many aspects of language, Saussure made clear the object of study for linguistics as a science. His ideas on the arbitrary nature of sign, on the relational nature of linguistic units, on the distinction of langue and parole and of synchronic and diachronic linguistics, etc. pushed linguistics into a brand new stage.