21. Passed from father to son, the music has not changed for eight centuries，and as you know, ________ knowledge of this music showed that you were ________real gentleman.
A. a; a B. the, 不填 C.不填;a D. the; the
22. —I am thinking of the test tomorrow. I am afraid I cannot pass this time.
—_________! I am sure you will make it.
A. Go ahead B. Good luck C. No problem D. Cheer up
