21.Using _____ illegal drugs can lead to health problems, and it can be _____ stain on one’s life.
A. 不填；the B. the; the C. the; a D. 不填； a
22. Everyone present at the meeting agreed to stick to the ________that everyone should be treated fairly.
A. purpose B. ambition C. principle D. level
23. _________ in the warm sunlight, I soon fell asleep on the sunny beach.
A. Bathe B. To bathe C. Bathed D. Bathing
