()建模最简便,且能满足数控车铣零件的需要。
A.线框模型
B.面模型
C.实体模型
D.特征模型
参考答案:C
It was in 1949 _____ the People's Republic of China was founded. [ ]
A. when
B. that
C. in which
D. which
客户在使用消息服务期间,服务费的计算和收取以()为基本单位。