单项选择题
A.is primarily designed for vessels operating up to 50 miles offshore or on foreign waters B.transmits a signal that can be detected by satellite C.must be manually activated D.operates in the medium and low frequency bands
A Class A EPIRB is NOT（）.A.approved by the CCSB.designe...
单项选择题A Class A EPIRB is NOT（）.
A.approved by the CCS B.designed for float free，automatic activation C.operated on 121.5/243 MHz D.operated manually
A check line is（）.A.a safety line attached to a man wor...
单项选择题A check line is（）.
A.a safety line attached to a man working over the side B.used to measure water depth C.used to slow the headway of a barge D.used to measure the overhead height of a bridge
（）is the course to reach you?A.WhatB.HowC.WhichD.When
单项选择题（）is the course to reach you?
A.What B.How C.Which D.When
