1. We work together to achieve our common purpose: ____ world that is safer, cleaner and healthier than ____ one we founded.
A. the; the B. a; 不填 C. a; the D. the; 不填
2. ---- Which of these digital cameras do you like best?
---- ______. They are both expensive and of little use.
A. None B. Neither C. Nothing D. No one
