单项选择题
Good anchorage may be obtained anywhere in this water area，the bottom being generally mud and sand，vessel may have（）.
A.good getting ground B.good holding ground C.good grabbing ground D.good handling ground
单项选择题 Geographic range is the maximum distance at which a light may be seen under（）.
单项选择题 Due to the shape of the sea anchor，the best way to haul it back aboard is by（）.
单项选择题 Deficient oxygen content inside a chain locker can be detected with（）.
