单项选择题
A.will add to B.will subtract from C.may add to or subtract from D.will not change
The variation for most given areas undergoes（）change，th...
单项选择题The variation for most given areas undergoes（）change，the amount of which is also noted on charts.
A.an annual B.a constant C.a variable D.an unstable
The quadrantal spheres are used to（）.A.Remove deviation...
单项选择题The quadrantal spheres are used to（）.
A.Remove deviation on the intercardinal headings B.Remove deviation on the cardinal compass headings C.Remove heeling error D.Compensate for induced magnetism in vertical soft iron
The MOST important feature of the material used for mak...
单项选择题The MOST important feature of the material used for making the binnacle of a standard magnetic compass is that it is（）.
A.nonmagnetic B.weatherproof C.corrosion resistant D.capable of being permanently affixed to the vessel
