单项选择题
VHF Radio is one of the very important navigational instruments on board，（）messages can be sent.
A.by which B.through which C.by that D.through that
单项选择题 Under the International Code of Signals how are geographical locations such as New York City transmitted?（）
单项选择题 The principal advantage of NAVTEX radio warnings is that（）.
单项选择题 The Master shall insure that the Emergency Position Indicating Radiobeacon (EPIRB) is（）.
