油气田的形成要素包括（）。
A、生油层
B、储集层和改成
C、圈闭
D、上述三项
参考答案：D
I just couldn't understand the former mayor _____ the money raised for children in poor areas.
A．taking
B．to take
C．being taken
D．to be taken
怎样制定生产考核办法？
