双壁管

double yellow lines───双黄线

double the size───两倍大小

double wedding───双人婚礼

double white lines───双白线

double dip───双减税；两地减税

double dipper───双重支薪人

double dips───双减税；两地减税

double eagle───n.（美）双鹰金元（美国旧币名，面值20美元）

double eagles───n.（美）双鹰金元（美国旧币名，面值20美元）

It reviewed the key points of processing technique and equipment for plastic double-walled corrugate pipe at home and abroad.───论述了国内外塑料双壁波纹管成型工艺和成型设备的技术要点。

considered that the metal and cement pipes would be replaced by the large sized plastics pipe, and the polyethylene double walled bellows would develop greatly.───表明，金属管、水泥管等传统埋地管材将被淘汰，取而代之的是大口径塑料埋地管，聚乙烯双壁波纹管将会获得大发展。

• double-walled tank
• double-walled pipe