按工艺要求电路板上-的焊点要呈锥状，并留有线尖，线尖外露不超过（）。
A.1mm
B.2mm
C.0.5m
D.0.2mm
参考答案：A
With the development of science and technology, news can be_______ to every corner of the world in seconds.
A． put out
B．sent out
C．run out
D．taken out
电气设备的避雷器是防止( )危险的防雷装置。
A．直击雷B．静电感应雷C．电磁感应雷D．雷电波入侵
