Distress signals may be().
A person’s attention is attracted ______ by the intensity of different signals as by their context, significance, and information content.
Which of the following devices can route electrical signals only when activated by an external control signal?()
GIVE DISTRESS SIGNALS FOR IDENTIFICATION.的意思是:发出遇险求救信号。
All of the following are distress signals under the Rules EXCEPT().
The service life of distress signals must be not more than().
All fog signals shall be sounded every two minutes with the exception of a vessel().
Which equipment is not a source of locating signals?()
The time interval between the transmission of signals from a pair of Loran-C stations is very closely controlled and operates with().
One of the signals,other than a distress signal,that can be used by a rescue boat to attract attention is a/an().