第30题: [单项选择]According to the passage, happiness is greatly dependent upon _________. A. a happy childhood B. a feeling that conditions are improving C. great fortune D. a college degree 参考答案:B 答案解析:[解析]事实细节题。文章第六段指出:人们在感到他们现有的水平提高时,感觉最幸福。故B)项与文意相符,为正确答案。[避错指导] 文章第六段第二句讲到“Children... have happier c