二重最小二乘法

Double blade sword,A Double-edged Sword,A Two-Edged Sword,Two-sided Sword

Double-Seventh Day；The Double Seventh Festival

Biotar lens【光】;double Gauss lens【光】

double flash electroretinogram

double thread shoe border stitcher

double-ended grinding machine【机】

double alternate method

double-line spectroscopic binary【天】