技术贸易通常表现为技术( )
A．一次性的转移
B．所有权的转移
C．使用权的交易
D．有形的商品交易
参考答案：C
— Are they about to have dinner?
— Yes, it____ in the dining room.
[ ]
A. is being served
B. is served
C. is serving
D. serves
自由弯曲终了时，凸、凹模对弯曲件进行了校正。（）
