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

Buoys are marked with reflective material to assist in their detection by searchlight. Which statement is TRUE? ()

A.A safe-water buoy will display red and white vertical stripes of reflective material
B.All reflective material is white because it is the most visible at night
C.A special-purpose mark will display either red or green reflective material to agree with its shape
D.A preferred-channel buoy displays either red or green reflective material to agree with the top band of color

微信掃碼免費搜題