问题补充：
People live longer and stay today than they did 50 years ago.
A. health
B. healthier
C. healthiest
D. the healthiest
答案：
A. health
(答案→)B. healthier
C. healthiest
D. the healthiest
解析：本题中含有比较结构than，故要用比较级，stay是连系动词，后应跟形容词healthy的比较级healthier，故选B。
