around the fire, the tourists danced with the local people.                                                                                                                                                                                                 

A．Gather

B．To gather

C．Gathering

D．To be gathering

零件装配中有些零件间的相互位置关系是不可乱的，以下哪种不属于这种情况（）

A.组合加工件

B.平衡件

C.配合副

D.正时件