单项选择题
A.lower low water B.high water C.low water D.sea level
Navigational charts are subject to frequent changes，the...
单项选择题Navigational charts are subject to frequent changes，the important ones of which are promulgated by （）.
A.Admiralty Notices to Mariners B.Mariner's Handbook C.Catalogue D.Sailing Directions
No navigational aids are shown and the chart is not kep...
单项选择题No navigational aids are shown and the chart is not kept corrected for alterations in depths inside the pecked lines. For more detailed information，the larger scale charts must be （）.
A.referred to B.appreciated C.met with D.concerned
Owing to old data of the survey the positions and numbe...
单项选择题Owing to old data of the survey the positions and number of the beacons shown on this chart are not to be （）.
A.considered B.insured C.relied upon D.suspected
