21. It’s _____ delight to have completed ______ ten-year research project with the desired result.
A. /; the B. a; the C. the; a D. a; a
22. There is still no cure for AIDS today, ______ caused great death of the patients.
A. that B. when C. where D. which
23. Shakespeare is considered as the greatest writer of world literature. ______ the plays, he has written some poems.
A. Apart from B. Except for C. Other than D. As well
