He is new comer to chemistry but he has made a few important discoveries.A. / /B. a /C.

问题补充：

He is new comer to chemistry but he has made a few important discoveries.

A. /, /

B. a, /

C. a, the

D. the, the

答案：

A. /, /

(答案→)B. a, /

C. a, the

D. the, the

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