对健康影响越来越大的因素是（）
A.卫生服务
B.自然环境
C.生物学
D.行为与生活方式
E.社会环境
参考答案：D
Visual FoxPro中不允许在主关键字字段中有重复值或 【6】 。
填空题。
1. In 1846, the United States____ (向……宣战 ) Mexico.
2. They _____ (定居 ;习惯于) new towns.
3. ____ (人们相信)that before long the mix of nationalities will be so great that there will be no
distinct major racial or cultural groups.
4. I ____ (一起合作 ) a couple from my hotel and hired a car.
5. He was puzzled by a math problem and then a new idea suddenly___ (使想起) him.
