（）标板是从白到黑有10个级差的拍摄标板。 A.快门速度 B.对焦精度 C.灰阶 D

今年上海世博会中国馆-“东方之冠”给人强烈的视觉冲击，它的主体结构为四根巨型钢筋混凝土制成的核心筒．其中钢属于（　　）

A．金属材料

B．硅酸盐材料

C．有机高分子材料

D．复合材料

存储转发交换技术中，通信子网的结点是( )。

A．源主机

B．路由器

C．通信控制处理机

D．电子或机电结合的交换设备

Beijing: The United States and North Korea had their first ______ in four months here this afternoon as part of the ______ negotiations on how to end North Korea’s nuclear program, but diplomats played down prospects for______. James A. Kelly, assistant ______, and Kim Yong Ⅱ, North Korea’s deputy foreign minister, met ______ of formal discussions, ______ on direct dialogue that began after a stormy meeting ______ in which North Korea warned that it was moving quickly to ______ nuclear arms. The Bush administration had insisted ______ that it would only hold talks with North Korea ______ because, it argued, only ______ pressure would persuade North Korea to______. It got its way when North Korea dropped its insistence on ______ and agreed, after extensive efforts by China, to hold unusual simultaneous negotiations with ______,______,______ and ______ as well as the United States. Though Bush administration officials had not ______ talking privately with the North Koreans during______, the fact that Mr. Kelly and Mr. Kim met on the first day was seen as a sign of ______ by the American side.

液压机的本体机构一般由哪几部分组成？

质量管理体系认证比质量管理体系审核多出的活动有（）。

A.认证的申请与受理

B.文件评审

C.纠正措施的验证

D.监督审核与复评

E.现场审核的实施