99色精品-9色在线-99色在线-99色视频 国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項選擇題

集裝箱是由龍門吊裝卸。()

A. Containers are loaded and discharged by gantry cranes.
B. Cases are loaded and discharged by gantry cranes.
C. Cases are loaded and discharged by heavy derricks.
D. Containers are loaded and discharged by heavy derricks.

微信掃碼免費搜題