--- Did your boss phone you again the next day?

--- No, it was a fortnight ____ he gave me a second call.

A．that

B．when

C．before

D．since

化学与生活、社会密切相关。下列做法正确的是

A．城市生活垃圾应分类处理，废旧电池回收后集中掩埋，废弃的塑料焚烧处理

B．若将原来燃烧液化石油气的灶具改成烧天然气，应增大空气进气量和减少天然气进入量

C．鉴别棉纺线与羊毛线可用灼烧法鉴别

D．糖尿病人可用氢氧化铜悬浊液检验其新鲜尿样中蔗糖含量的高低