单项选择题
（）day，pilot flag should be displayed from main mast．
A.From B.By C.on D.With
单项选择题 The heights and soundings of Admiralty chart are expressed（）in Fathoms（）in Meters．
单项选择题 （）is not contained in the NM Weekly.
单项选择题 （）are published for the correction of Admiralty Charts．
