Dây nhôm lõi thép được sử dụng phổ biến nhất ở các đường dây có mức điện áp là ?

Holgraphic talking which is projections of talking

Which of the following is an example of an opposing signal? no examplthates given.   i would say, that traffic lights in a city at major intersections direct the flow of traffic in opposite directions so would be an example.also, stop signs on either side of the same street would be an example. at a train crossing, the light for allowing car traffic in opposite directions or not would be another example.