The old scientist has made growing and researching rice.A.contribution atB.contr
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The old scientist has made ________ growing and researching rice.
A.contribution at
B.contribution to
C.contribution for
D.an effort
试题答案
B
从句意分析不难看出空格内的名词应与make构成短语，表示“作贡献”，要注意D项后面应接不定式。