可以为上网用户提供DNS域名服务器地址的为（）。
A.SGSN
B.GGSN
C.内部DNS
D.用户端手动配置
参考答案：B, D
—When__________ and visit our exhibition next month?
— When_______, I will let you know.
A．will he come; he will come
B．will he come; he comes
C．does he come; he will come
D．does he come; he comes
在商场服务时“一懂”、“三会”指的是什么？
