以下那个信令可以发起GPRS上行资源请求:() ["Packet Downlink Ack/Nack","Packet Downlink Assignment","Packet Downlink Dummy Control","Packet Uplink Ack/Nack"]
确定工艺余量时,()考虑零件加工过程中温度的影响。 ["应该","不应该","不一定","不需要"]
“三专两闭锁”其工作情况为()。
在化合物Ca(ClO)2中氯离子的化合价为()。 ["A、+1","B、-1","C、+7","D、+5"]
注塑模架定模板可称为()。 ["A板","公模板","母模板","B板","前模板"]
杂散电流测定仪的测定原理是什么?