喷涂时，手提式静电喷枪枪口距离工件应大于（）。
A.200mm
B.250mm
C.280mm
D.300mm
参考答案：B
---It's time ．
---I'm coming, mum.
A．for breakfast
B．have breakfast
C．for I to have breakfast
D．for have breakfast
掌上百度都有什么功能？怎样使用？
