正注水井测压降曲线时,必须关闭()。
A、总阀门
B、测试阀门
C、来水阀门和生产阀门
D、套管阀门
参考答案:C
The girl witnessed________the man burst into the bank on a rainy night.[ ]
A. to see
B. seeing
C. to seeing
D. having seen
简述遗赠的概念和有效条件。