The new device uses a rotary mechanism similar to ball joint to eliminate the unscrewing torque caused by the reciprocating motion of the rod string.是什么意思_The new device uses a rotary mechanism similar to ball joint to eliminate the unscrewing torque caused by the reciprocating motion of the rod string.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句