单项选择题
Mariners should pay much attention in the overlapped area owing to（）.
A.complicated circumstances B.changeable atmospheric pressure C.large density of traffic D.some strong signals from unwanted satellites
单项选择题 The satellites over the major ocean regions cover the globe（）.
单项选择题 The Inmarsat system has five major components, they are:（）.
单项选择题 The INMARSAT consists of（）major components.
