He made no preparation for the job interview in advance, which might_____ his failure in it.

A．bring up

B．account for

C．contribute to

D．agree with

用含Cu₂S的铜矿冶炼铜有多种方法。其中之一是：

(1)先通入空气将矿石高温煅烧，生成两种氧化物；

(2)将煅烧所得的固体氧化物加上和它质量相同的未经煅烧过的矿石，混会均匀后隔绝空气再进行高温煅烧，结果得到金属铜和一种有刺激性气味的气体。      

写出上述反应的化学方程式：      

(1) __________________________________________________________________；      

(2) __________________________________________________________________。