Science and technology have in important ways to the improvement of agricutural production.
A. attached
B. assisted
C. contributed
D. witnessed
网友回答
A. attached
B. assisted
(答案→)C. contributed
D. witnessed
解析：句意：科学技术在提高农产品的产量上作出了重要的贡献。attach …to 把… …附加在……上；assist帮助；contribute…to作贡献于；witness见证。故选C。