25. The most important thing about cotton in history is _____ part that it played in _____ Industrial Revolution.
A. /; / B. the; / C. the; / D. the; the
26. Various summer camps being available, we can choose ______ based on our own interest.
A. either B. each C. one D. it
27. The guard at the gate insisted that everybody ________ the rules.
A. obeys B. obey C. will obey D. would obey
