21.Although it had been _____ struggle for him to finish ______ experiment, he enjoyed the result with_______ satisfaction.
A. the; an; / B. a; the ; / C. a; an; a D. /; the; a
22. He was so excited and insisted that what he had done completely______ their demand（要求）.
A. met B. meet C. should meet D. has met
23. Our English teacher is ______ our teacher; she is also our best friend.
A. rather than B. other than C. more than D. less than
