常見(jiàn)例句雙語(yǔ)例句The derrick man, positioned at the crown block, is to advise the driller when the snake is coming through the crown sheave.井架工看守在天車(chē)上,儅蛇皮接繩器到達(dá)天車(chē)時(shí),通知司鑽。blog.sina.com.cn 返回 derrick block