问题补充：
It was nothing but his ten years of hard work that his success in his research.
A. referred to
B. applied to
C. led to
D. appealed to
答案：
A. referred to
B. applied to
(答案→)C. led to
D. appealed to
解析：本题考查动词短语辨析。题干是个强调句型，主体部分是nothing but his ten years of hard work his success in his research。句意：十年艰苦的工作导致了他的研究成功。A. refer to 谈到；提及；B. apply to应用于； C. lead to 导致。D. appeal to吸引。
