选择题:A.4M/3a,2M/3a B.-4M/3a,-2M/3a C.4M/3a,-2M/3a D.-4M/3a,2M/3a 题目分类:结构工程师 题目类型:选择题 号外号外:注册会员即送体验阅读点! 题目内容: A.4M/3a,2M/3aB.-4M/3a,-2M/3aC.4M/3a,-2M/3aD.-4M/3a,2M/3a 参考答案: 答案解析: