21.That was _____ time when girl's education was always placed ____ second to boy's.
A. a; a B. the; the C. /; / D. a; /
22. I shall never forget those years _____ I studied in the school with my classmates and teachers，______ has a great effect on my life．
A. that; which B. when; which C. which; that D. when; who
