下列相互作用的过程中，可以认为系统动量守恒的是[ ]
A．
B．
C．
D．
AC
Nowadays, many people walk to work _____ Copenhagen Conference calling for living a low-carbon lifestyle
to cope with global warming. [ ]
A. in relation to
B. in response to
C. in addition to
D. in opposition to
在华中世纪星系统数控机床中调刀与换刀指令格式为（）。
A．T¬_
B．M06
C．M06T_
D．T_M06
