目前，先进国家普遍采用硅芯塑管作为光缆通信干线及高速公路通信的管道。
Recent years Silicon Core Tube is widely adopted as pipes of optical cable backbones and expressway communications in developed countries.
但是与国家和省级干线公路不同，县乡公路主要由技术等级在二级和二级以下的公路所构成。
However, the rural road is different from main roads of state or province level in that it is mainly composed of roads whose technical degree is of or under the second degree.
中东欧国家拥有天然良港，与铁路、公路等交通干线连接起来，可以发挥巨大的综合效应。
The quality ports in CEECs, once connected with rail lines, highways and other transport arteries, will have a major role to play in many fields.
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