She is newcomer to chemistry but she has already made some important discoveries.A. the;

She is newcomer to chemistry but she has already made some important discoveries.
A. the; the
B. the; /
C. a; /
D. a; the

A. the; theB. the; /(答案→)C. a; /D. a; the解析：考查冠词：第一空是泛指：一个新来的人，第二空不填，因为chemistry是学科，前面不加冠词。句意：她是刚刚学习化学的，但她已经有一些重要发现了。选Ｃ。

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