中央预告信号装置在供电系统发生故障和不正常工作状态时发出（）
A、电笛
B、光字信号
C、电铃
D、闪光
参考答案：B, C
漏斗胸(pectusexcavatum)
WebSQL is a SQL-like (1)language for extracting information from the web. Its capabilities for performing navigation of web (2)make it a useful tool for automating several web-related tasks that require the systematic processing of either all the links in a(3),all the pages that can be reached from a given URL through (4)that match a pattern,or a combination of both. WebSQL also provides transparent access to index servers that can be queried via the Common (5)Interface.
空白（5）处应选择（）
A.Router
B.Device
C.Computer
D.Gateway
