单选题 In the last paragraph, Roman expansion was described vividly, what is the base of the expasion?

【正确答案】 C
【答案解析】[解析] 见第二段末:“It was,in fact,the internal stability of the Republic which made expansion possible.”而“军事侵略”只是这种扩张的基本形式,不是基本原因。