21. While he was investigating ways to improve the telescope, Newton made ________ discovery which completely changed ________ man’s understanding of color.
A. a; £¯ B. a; the C. £¯; the D. the£»a
22. Music should be taught routinely in schools because of the benefits ________ can have on the development of the brains of young children.
A. which B. that C. it D. one