电离层地球大气的高空魔镜 通讯、广播、导航都离不开它

百度 凤凰网财经3月25日讯（杨芳）3月23日凌晨，特朗普在白宫正式签署对华贸易备忘录，依据美国贸易代表办公室公布的301调查报告，将对从中国进口的商品大规模征收关税，并限制中国企业对美投资并购。

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