单项选择。
______ are you sending your letter?[ ]
A. Where
B. Who
C. Which
D. What
答案:A
In the traffic accident, his father came close to________ .
A.bekilled
B.beingkilled
C.kill
D.killing
裸眼完井时,钻头钻至油层顶界附近后,下技术套管注水泥固井,然后再用小钻头钻穿油层至设计井深完井,此种完井方法称为()。
A、先期完井
B、后期完井
C、割缝衬管完井
D、尾管完井