短語詞組短語derrick head span block 吊桿頭跨繩滑車derrick head purchase block 上吊貨滑車derrick head cargo block 吊桿頭起貨滑車;吊桿頭起重滑車;上吊貨滑車derrick head shipment block 吊桿頭起貨滑車derrick k head cargo block 吊桿頭起貨滑車 返回 derrick head block