从井筒内分析，引起注水井压力变化的因素是（）。
A、封隔器失效
B、配水器被堵或脱落
C、管外窜槽
D、压力表损坏
参考答案：A, B, C
名义GDP
What are the plans of Wal-mart in China().
A. To buy the retail stores of Trust-Mart.
B. To allow the presence of labor unions into Wal-Mart.
C. To become the biggest food and department store network.
D. All except c.
