干气主要形成在哪个阶段？（）
A.生物化学生气阶段
B.热裂解生凝析气阶段
C.深部高温生气阶段
D.热催化生油气阶段
参考答案：C
It's reported that Nanjing South Railway Station _______ at the end of this month.[ ]
A.has been completed
B.is completed
C.was completed
D.will be completed
在Visual FoxPro中项目文件的扩展名是【2】。
