Many years of hard work his great success in the development of this new type of material.

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A. due to
B. thanks to
(答案→)C. contributed to
D. looked into
解析：本题考查词义、词性。本句缺少谓语，应选动词。A项和B项意思都是“由于，因为”，皆为介词，故可排除；D项意为“调查，往里看”，语意不通；C项意思是“对……有贡献，有助于……”,故C项为正确答案。整句意为“这种新型材料的研发之所以能取得巨大成功得益于他多年的辛苦工作”。