meteoroid的音标：meteoroid的英式发音音标为：['mi:tjərɔɪd]meteoroid的美式发音音标为：['mitɪərˌɔɪd]...

The cometary ejection play a crucial role in formation and evolution of the meteoroid stream.彗星的喷发速度在流星群的演化过程中起着重要作用....

n.流星体...