21. Of all _______ reasons for my decision to become a university professor, my father’s advice was _______ most important one.
A. the; a B. /; a C. /; the D. the; the
22.Healthy diet should ________ some nutrition (营养素), ________ sugar, protein and calcium.
A. contain; included B. containing; including
C. be contained; included D. contain; including
