单项选择题
Radar makes the most accurate determination of the（）.
A.direction of a target B.distance to a target C.size of a target D.shape of a target
单项选择题 Most modern Loran-C receivers，when not tracking properly，have a（n）（）.
单项选择题 Loran-C uses the multiple pulse system because（）.
单项选择题 Loran-C is which type of system（）.
