常见的井下工程事故有:卡钻事故;钻具事故;钻头事故;落物事故;();顿钻事故;卡电缆、卡仪器事故。
参考答案:井喷及井喷失控事故
The teacher told his students that the earth _____ round the sun. [ ]
A. go
B. went
C. goes
D. had gone
五加皮的气味是()
A.气微,味微甜后酸
B.气香,味苦而后甜
C.气微香,味微辣而苦
D.有败油气,味淡
E.有浓厚的香气,味苦、稍有麻舌感