Copper, mostly.

大多数是因为铜。

youdao

But stainless steel tube outer wall and the outer wall of the copper pipe which pipe bead setting more is still unclear, but can say two pipe wall mostly film condensation.

但不锈钢管外壁和铜管外壁哪种管材的珠状凝结更多尚不清楚，但可以说两种管材外壁大部份是膜状凝结。

youdao

Copper deposits in the south east districts of Hubei province are mostly of skarn rock having simple ore properties.

鄂东南地区的铜矿床大多属于矿石性质简单的矽卡岩矿。

youdao

It is made mostly of copper. Throughout history,images of liberty have been represented as a woman.

VOA: special.2009.06.29

With the environmental benefits of a hybrid come environmental costs: 30 extra pounds of copper, mostly in the motor windings, and 22 pounds of nickel in the battery.

FORBES: Feel Green, Feel Good

Metals prices were mostly up slightly during the week-long reporting window to Oct. 30, with only platinum and copper down.

FORBES: FOCUS: Speculators Continue To Cut Metals Positions Across The Board -- CFTC