第20题: [单项选择]The direct reason for specialization is ______. A. the development in communication B. the growth of professionalisation C. the expansion of scientific knowledge D. the splitting up of academic societies 参考答案:C 答案解析:事实细节题。文章第一句便明确说明科学知识的日积月累是专业化的直接原因,所以C为正确答案。