某分部工程双代号网络计划如下图所示，其关键线路有（）条。
A．2
B．3
C．4
D．5
参考答案：C
(2009陕西宝鸡质检)People eat vegetables per person today as they did ten years ago.
A．as twice many
B．as twice as many
C．twice as many as
D．twice as many
水环境容量
