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Science and technology have ____in important ways to the improvement of agricultural production.

A.     attached  B. assisted  C. contributed  D. witnessed

Science and technology have ____in important ways to the improvement of agricultural production.

A.     attached  B. assisted  C. contributed  D. witnessed

.Science and technology have ____in important ways to the improvement of agricultural production.

A.attached         B. assisted         C. contributed        D. witnessed