矢锥
参考答案:
打捞钻杆、岩芯管和套管用的表面有螺纹刃的锥形工具。
Stand up _____ you fall down, and I'm sure you'll succeed in time.[ ]
A. until
B. where
C. before
D. which
左前斜位心影后缘下部是哪个房室的投影
A.右心房B.右心室C.肺动脉圆锥D.左心房E.左心室