《城市区域环境噪声标准》（GB3096-2008）规定的3类标准夜间为（）DBA。
A、40
B、45
C、50
D、55
参考答案：D
—What is the Group G8?
—Oh, it is a group ________ the eight of the richest countries or areas of the
world.
A．consisting of
B．consists of
C．consisted of
D．is consisted of
在WindowsXP系统下将文件彻底删除可用（）键操作。
A、Alt+Del
B、Shift+Del
C、Alt+/
D、Ctrl+Del
